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Note: This page contains sample records for the topic "frequency variable voltage" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


1

Variable Frequency Drives  

NLE Websites -- All DOE Office Websites (Extended Search)

How BPA Supports VFDs Rebates are available from your utility for Variable Frequency Drives on pumps 20hp or greater and storage fans.. Energy savings from VFDs vary and can...

2

Variable Frequency Pump Drives  

E-Print Network (OSTI)

-frequency electric motor drive. What is happenin9 with variable frequency driven pun,ps is a classical illustration that evolution in technical products takes place not only because of changes in the processes served by these products, or because of innovations...-pole 3550 rpm squirrel caqe induction motor became available in the early 1930s that high pressure pumps operating at that speed could be buil t. And now, in the 1980s, the development of the solid-state, variable frequency electric motor drive...

Karassik, I. J.; Petraccaro, L. L.; McGuire, J. T.

3

Variable frequency microwave furnace system  

DOE Patents (OSTI)

A variable frequency microwave furnace system (10) designed to allow modulation of the frequency of the microwaves introduced into a furnace cavity (34) for testing or other selected applications. The variable frequency microwave furnace system (10) includes a microwave signal generator (12) or microwave voltage-controlled oscillator (14) for generating a low-power microwave signal for input to the microwave furnace. A first amplifier (18) may be provided to amplify the magnitude of the signal output from the microwave signal generator (12) or the microwave voltage-controlled oscillator (14). A second amplifier (20) is provided for processing the signal output by the first amplifier (18). The second amplifier (20) outputs the microwave signal input to the furnace cavity (34). In the preferred embodiment, the second amplifier (20) is a traveling-wave tube (TWT). A power supply (22) is provided for operation of the second amplifier (20). A directional coupler (24) is provided for detecting the direction of a signal and further directing the signal depending on the detected direction. A first power meter (30) is provided for measuring the power delivered to the microwave furnace (32). A second power meter (26) detects the magnitude of reflected power. Reflected power is dissipated in the reflected power load (28).

Bible, Don W. (Clinton, TN); Lauf, Robert J. (Oak Ridge, TN)

1994-01-01T23:59:59.000Z

4

Variable frequency microwave furnace system  

DOE Patents (OSTI)

A variable frequency microwave furnace system designed to allow modulation of the frequency of the microwaves introduced into a furnace cavity for testing or other selected applications. The variable frequency microwave furnace system includes a microwave signal generator or microwave voltage-controlled oscillator for generating a low-power microwave signal for input to the microwave furnace. A first amplifier may be provided to amplify the magnitude of the signal output from the microwave signal generator or the microwave voltage-controlled oscillator. A second amplifier is provided for processing the signal output by the first amplifier. The second amplifier outputs the microwave signal input to the furnace cavity. In the preferred embodiment, the second amplifier is a traveling-wave tube (TWT). A power supply is provided for operation of the second amplifier. A directional coupler is provided for detecting the direction of a signal and further directing the signal depending on the detected direction. A first power meter is provided for measuring the power delivered to the microwave furnace. A second power meter detects the magnitude of reflected power. Reflected power is dissipated in the reflected power load. 5 figs.

Bible, D.W.; Lauf, R.J.

1994-06-14T23:59:59.000Z

5

Coordination of Voltage and Frequency Feedback in Load-Frequency Control Capability of Wind Turbine  

E-Print Network (OSTI)

Coordination of Voltage and Frequency Feedback in Load-Frequency Control Capability of Wind Turbine-Frequency Control (LFC) is gradually shifted to Variable Speed Wind Turbines (VSWTs). In order to equip VSWT@et.aau.dk Abstract--In near future, with high penetration of Wind Energy (WE) in power system, the burden of Load

Silva, Filipe Faria Da

6

Variable frequency microwave heating apparatus  

DOE Patents (OSTI)

A variable frequency microwave heating apparatus (10) designed to allow modulation of the frequency of the microwaves introduced into a multi-mode microwave cavity (34) for testing or other selected applications. The variable frequency microwave heating apparatus (10) includes a microwave signal generator (12) and a high-power microwave amplifier (20) or a high-power microwave oscillator (14). A power supply (22) is provided for operation of the high-power microwave oscillator (14) or microwave amplifier (20). A directional coupler (24) is provided for detecting the direction and amplitude of signals incident upon and reflected from the microwave cavity (34). A first power meter (30) is provided for measuring the power delivered to the microwave furnace (32). A second power meter (26) detects the magnitude of reflected power. Reflected power is dissipated in the reflected power load (28).

Bible, Don W. (Clinton, TN); Lauf, Robert J. (Oak Ridge, TN); Johnson, Arvid C. (Lake in the Hills, IL); Thigpen, Larry T. (Angier, NC)

1999-01-01T23:59:59.000Z

7

Chapter 18: Variable Frequency Drive Evaluation Protocol  

SciTech Connect

An adjustable-speed drive (ASD) includes all devices that vary the speed of a rotating load, including those that vary the motor speed and linkage devices that allow constant motor speed while varying the load speed. The Variable Frequency Drive Evaluation Protocol presented here addresses evaluation issues for variable-frequency drives (VFDs) installed on commercial and industrial motor-driven centrifugal fans and pumps for which torque varies with speed. Constant torque load applications, such as those for positive displacement pumps, are not covered by this protocol. Other ASD devices, such as magnetic drive, eddy current drives, variable belt sheave drives, or direct current motor variable voltage drives, are also not addressed. The VFD is by far the most common type of ASD hardware. With VFD speed control on a centrifugal fan or pump motor, energy use follows the affinity laws, which state that the motor electricity demand is a cubic relationship to speed under ideal conditions. Therefore, if the motor runs at 75% speed, the motor demand will ideally be reduced to 42% of full load power; however, with other losses it is about 49% of full load power.

Romberger, J.

2014-11-01T23:59:59.000Z

8

STATCOM-based voltage and frequency regulator for stand-alone asynchronous generator  

Science Journals Connector (OSTI)

This paper presents a STATCOM-based voltage and frequency regulation for stand-alone asynchronous generator feeding linear and nonlinear loads. The SEIG have inherent poor voltage and frequency regulation. The voltage and frequency depend upon the load current and power factor of the load with fixed excitation capacitor employing unregulated turbines. The changing consumer load requires variable reactive power compensation for excitation requirement. Consumer load contains harmonics and performance of SEIG is largely affected by these load harmonics. A current controlled voltage source inverter working as STATCOM is used for harmonic elimination, load balancing and variable reactive power compensation. A DC chopper with dump load is connected across DC bus capacitor to regulate varying consumer load. The control algorithm has been first co-simulated with processor in the loop (PIL) and then experimentally validated. The transient behaviour of developed prototype system for application and removal of balanced, unbalanced, nonlinear load is investigated.

Dheeraj Kumar Palwalia

2014-01-01T23:59:59.000Z

9

A novel voltage and frequency controller for standalone DFIG based Wind Energy Conversion System  

Science Journals Connector (OSTI)

Abstract This paper presents a new speed-sensorless control strategy for a stand-alone doubly-fed induction generator supplying energy to an isolated load. The method is based on the root mean square (rms) detection scheme. The generated stator voltage is controlled via rotor currents. Amplitude of stator voltage and its frequency are controlled simultaneously. The output signals from the voltage controllers are the reference signals for the rotor current amplitude and frequency of the stator voltage is regulated with the help of frequency control loop. This developed direct voltage control method is applicable for both the balanced and unbalanced load and also for standalone and grid connected mode. The control pulses for the rotor side converter is supplied by the hysteresis controller which is operated on the error signal calculated between actual and reference rotor currents. This paper also provides the brief idea about the voltage and frequency control on modern Autonomous DFIG based Wind Energy Systems via single phase mathematical model of standalone DFIG system. A short state-of-the-art review on mechanical position/speed sensorless control schemes for autonomous DFIG based \\{WESs\\} is presented, which helps the present researcher and students working in this area. These include stator flux oriented control techniques; direct voltage control techniques; MARS observer based techniques for autonomous DFIG-based variable-speed WESs. Simulation results obtained from a 2MVA DFIG system, prototype in MATLab/Simulink, are presented and discussed in this paper.

Rishabh Dev Shukla; Ramesh Kumar Tripathi

2014-01-01T23:59:59.000Z

10

INSTALLATION, COMMISSIONING AND TROUBLE SHOOTING OF VARIABLE FREQUENCY DRIVE.  

E-Print Network (OSTI)

??In this thesis, the installation of variable frequency drive on board a ship is introduced briefly. In this particular study the variable frequency drive was… (more)

Kuituniemi, Santtu

2013-01-01T23:59:59.000Z

11

Adhesive bonding using variable frequency microwave energy  

DOE Patents (OSTI)

Methods of facilitating the adhesive bonding of various components with variable frequency microwave energy are disclosed. The time required to cure a polymeric adhesive is decreased by placing components to be bonded via the adhesive in a microwave heating apparatus having a multimode cavity and irradiated with microwaves of varying frequencies. Methods of uniformly heating various articles having conductive fibers disposed therein are provided. Microwave energy may be selectively oriented to enter an edge portion of an article having conductive fibers therein. An edge portion of an article having conductive fibers therein may be selectively shielded from microwave energy.

Lauf, Robert J. (Oak Ridge, TN); McMillan, April D. (Knoxville, TN); Paulauskas, Felix L. (Oak Ridge, TN); Fathi, Zakaryae (Cary, NC); Wei, Jianghua (Raleigh, NC)

1998-01-01T23:59:59.000Z

12

Adhesive bonding using variable frequency microwave energy  

DOE Patents (OSTI)

Methods of facilitating the adhesive bonding of various components with variable frequency microwave energy are disclosed. The time required to cure a polymeric adhesive is decreased by placing components to be bonded via the adhesive in a microwave heating apparatus having a multimode cavity and irradiated with microwaves of varying frequencies. Methods of uniformly heating various articles having conductive fibers disposed therein are provided. Microwave energy may be selectively oriented to enter an edge portion of an article having conductive fibers therein. An edge portion of an article having conductive fibers therein may be selectively shielded from microwave energy. 26 figs.

Lauf, R.J.; McMillan, A.D.; Paulauskas, F.L.; Fathi, Z.; Wei, J.

1998-09-08T23:59:59.000Z

13

Adhesive bonding using variable frequency microwave energy  

DOE Patents (OSTI)

Methods of facilitating the adhesive bonding of various components with variable frequency microwave energy are disclosed. The time required to cure a polymeric adhesive is decreased by placing components to be bonded via the adhesive in a microwave heating apparatus having a multimode cavity and irradiated with microwaves of varying frequencies. Methods of uniformly heating various articles having conductive fibers disposed therein are provided. Microwave energy may be selectively oriented to enter an edge portion of an article having conductive fibers therein. An edge portion of an article having conductive fibers therein may be selectively shielded from microwave energy. 26 figs.

Lauf, R.J.; McMillan, A.D.; Paulauskas, F.L.; Fathi, Z.; Wei, J.

1998-08-25T23:59:59.000Z

14

Theory and practice of dynamic voltage/frequency scaling in the high performance computing environment.  

E-Print Network (OSTI)

?? This dissertation provides a comprehensive overview of the theory and practice of Dynamic Voltage/Frequency Scaling (DVFS) in the High Performance Computing (HPC) environment. We… (more)

Rountree, Barry Louis

2010-01-01T23:59:59.000Z

15

Comparative study of voltage oriented and frequency coordinated control of grid connected doubly fed induction generator  

Science Journals Connector (OSTI)

In this paper a comparative study between voltage oriented control (VOC) and frequency coordinated control (FCC) of grid connected doubly fed induction generator (DFIG) is presented. The two method controls are deeply done on DFIG converter sides grid side converter (GSC) and rotor side converter (RSC). The VOC method permanently maintains the DFIG reactive power to zero values to achieve stable voltage. This control is implemented by regulating the rotor direct axis reference current in RSC using grid reactive power. On the other hand the FCC has employed the active power obtaining from the system frequency deviation to control the rotor quadrature axis reference current in the RSC. The GSC is the same in two studies and its applied vector controlled method. The comparison study between the two methods is conducted at a steady and dynamic state under constant and variable wind speeds. The simulation results are carried out by using PSCAD/EMTDC electromagnetic transient program to validate the comparison study between two methods control of DFIG. The outcomes of the simulation show that the VOC is very convenient when the DFIG operated at transient mode and variable wind speeds while the FCC is feasible and effective for steady-state mode applications. Furthermore the FCC method has an ability to reduce the active and reactive powers ripples as well as decreasing torque harmonics. Both of two methods had fewer transient recovery values of output parameters which ensure safety dynamic response of DFIG and power system. This study contributes significantly to choose the suitable control of the DFIG converters according to electrical grid operation conditions. In addition if a joint control has been applied to these two methods the wind power gained strong and flexible control of the frequency and voltage for different operating conditions.

Li Yang

2014-01-01T23:59:59.000Z

16

Energy Aware Dynamic Voltage and Frequency Selection for Real-Time Systems with Energy Harvesting  

E-Print Network (OSTI)

Energy Aware Dynamic Voltage and Frequency Selection for Real-Time Systems with Energy Harvesting}@binghamton.edu Abstract In this paper, an energy aware dynamic voltage and frequency selection (EA-DVFS) algorithm energy and the harvested energy in a future duration. Specifically, if the system has sufficient energy

Qiu, Qinru

17

Impact of Wind Generation Variability on Voltage Profile of Radial Power Systems  

Science Journals Connector (OSTI)

This paper provides the results of a study conducted to assess the impacts of the "wind generation variability" on the voltage profile in a small-scale radial power system. The power network has been modeled using one of the well-known simulation programs ... Keywords: Wind Generation, Voltage Profile, Power Grids, Voltage Impacts, Minimum Singular Value, SSV index

M. O. Alruwaili; M. Y. Vaziri; S. Vadhva; S. Vaziri

2013-04-01T23:59:59.000Z

18

Variable Voltage Substation Electric Fire and Emergency Response  

Energy.gov (U.S. Department of Energy (DOE))

Variable Voltage Substation Electric Fire and Emergency Response My question is from an emergency response perspective. You stated that it took ~ ˝ for electricians to de-energize the electrical components before firefighters were allowed in to fight the fire. This delay causes more damage to equipment and potential propagation of the fire. Is there not a “master” breaker or switch? You’ve brought up a very good point. It gave me a good opportunity to discuss this with our Facilities Department and get a better understanding of the infrastructure upgrade plans. The direct answer to your question is “Yes, but…” Yes, there are “master” breakers and switches, but we can’t control them remotely. SLAC’s AC electrical distribution system at present is manual breakers – we have not installed the infrastructure to remotely control them (except see below). We recently underwent an upgrade to our Master Substation that will allow us to remotely control some high voltage breakers in the future, but we aren’t there yet. We do recognize the value in having this capability (and more importantly, our vulnerability in NOT having it), and have begun the preliminary planning to make this happen. One issue were are working on is cyber security for the power distribution networked infrastructure. Before we install the capability to remotely control the main electrical breakers, we are planning the infrastructure with our Information Technologies organization to ensure we have a robust secure network that is protected from unauthorized access. Once the cyber security issues are addressed and funded, we’re probably 5-10 years out from having remote operation capability due to limited resources to fund and install the infrastructure. Having said the above, we do have the capability of remotely opening the VVS Secondary Main Breakers – the ones that send power to the modulator distribution breakers - from our control room. Those breakers are integral parts of our safety systems in that interlock violation causes the breakers to open and remove power to the klystrons. But everything else is manual only. That remote operation capability would not have helped us in this case, as the VVS Secondary Main Breaker was the one that fried. We needed to open the breaker upstream of the VVS. Thanks for your interest. Let me know if I can provide further information.

19

Current mode integrators and their applications in low-voltage high frequency CMOS signal processing  

E-Print Network (OSTI)

Low voltage CMOS fully differential integrators for high frequency continuous-time filters using current-mode techniques are presented.. Current mode techniques are employed to avoid the use of the floating differential pair, in order to achieve...

Smith, Sterling Lane

2012-06-07T23:59:59.000Z

20

Load Shedding Algorithm Using Voltage and Frequency Data.  

E-Print Network (OSTI)

??Under frequency load shedding schemes have been widely used, to restore power system stability post major disturbances. However, the analysis of recent blackouts suggests that… (more)

Joshi, Poonam

2007-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "frequency variable voltage" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


21

Voltage and Frequency Control in Offshore Wind Turbines Connected to Isolated Oil Platform Power Systems  

Science Journals Connector (OSTI)

Offshore wind turbines have potential to supply offshore oil and gas platforms in the North Sea with electric energy. For remote located facilities it is attractive to pursue a solution where the wind turbines and oil platform operate in an isolated system. To study the operational properties of a system with these characteristics is necessary to identify possible advantages and disadvantages. This paper demonstrates how added voltage and frequency control in wind turbines equipped with full power electronic converters can improve the voltage and frequency stability in offshore oil and gas installations. The work is based on an electrical simulation model built in the PSCAD software. In the proposed transient simulation scenarios, the voltage dip is reduced from 16% to 6%, while the frequency overshoot is reduced from 97% to 25%. These are significant improvements that should be taken into consideration when offshore wind power is evaluated as power supply to oil installations.

Atle Rygg Ĺrdal; Tore Undeland; Kamran Sharifabadi

2012-01-01T23:59:59.000Z

22

STATCOM based voltage-frequency regulation for SEIG driven by an uncontrolled speed turbine  

Science Journals Connector (OSTI)

This article presents the analysis and the control of a stand-alone self excited induction generator (SEIG) intended for rural applications. SEIG along with the STATCOM with battery energy storage (BES) in its DC side makes it possible to control the terminal voltage and frequency during rotor speed and load variation. Constant frequency control is carried out by the load angle '?', without rotor speed control, while constant terminal voltage control is achieved via the modulation index 'm'. The 'SEIG' magnetisation characteristic and the 'STATCOM' rating are taken into consideration to determine the load interval where the terminal voltage and frequency can be controlled. The simulation results show good performances of the SEIG-STATCOM system under different perturbations.

Azzeddine Benlamoudi; Rachid Abdessemed

2009-01-01T23:59:59.000Z

23

Present and Future Modes of Low Frequency Climate Variability  

SciTech Connect

This project addressed area (1) of the FOA, “Interaction of Climate Change and Low Frequency Modes of Natural Climate Variability”. Our overarching objective is to detect, describe and understand the changes in low frequency variability between model simulations of the preindustrial climate and simulations of a doubled CO2 climate. The deliverables are a set of papers providing a dynamical characterization of interannual, decadal, and multidecadal variability in coupled models with attention to the changes in this low frequency variability between pre-industrial concentrations of greenhouse gases and a doubling of atmospheric concentrations of CO2. The principle mode of analysis, singular vector decomposition, is designed to advance our physical, mechanistic understanding. This study will include external natural variability due to solar and volcanic aerosol variations as well as variability internal to the climate system. An important byproduct is a set of analysis tools for estimating global singular vector structures from the archived output of model simulations.

Cane, Mark A.

2014-02-20T23:59:59.000Z

24

Variable Frequency Drives: Energy Savings and Impact on Motor Performance  

E-Print Network (OSTI)

Variable frequency drives (VFDs) have found widespread application in recent years. VFDs are valued for their potential to save energy and improve processes. Reliability has improved significantly, but there are still pitfalls to be addressed...

Petro, D.

25

Conservation Theory Process Control Using Variable Frequency Drives  

E-Print Network (OSTI)

The purpose of this paper is to outline some of the economic considerations of variable frequency control and to point out possible applications in order to create greater awareness of the options available to the engineer as he develops new...

Myers, N. S.

1980-01-01T23:59:59.000Z

26

On the efficiency of electrical submersible pumps equipped with variable frequency drives: A field study  

SciTech Connect

A field study was conducted on 18 electrical-submersible-pump- (ESP-) equipped wells operating in the Williston basin. Fifteen of these wells were run with variable frequency drives (VFD`s). The purpose of the study was to determine the efficiency and operating characteristics of ESP`s operating with VFD`s and compare them to those without. Voltage, current, power, and frequency were measured at the drive input, the drive output, and ESP input. Production data were recorded and power and efficiency were calculated at all measurement locations and compared to published data.

Patterson, M.M. [Patterson (Maurice M.), Hemphill, TX (United States)

1996-02-01T23:59:59.000Z

27

Optimizing performance per watt on GPUs in High Performance Computing: temperature, frequency and voltage effects  

E-Print Network (OSTI)

The magnitude of the real-time digital signal processing challenge attached to large radio astronomical antenna arrays motivates use of high performance computing (HPC) systems. The need for high power efficiency (performance per watt) at remote observatory sites parallels that in HPC broadly, where efficiency is an emerging critical metric. We investigate how the performance per watt of graphics processing units (GPUs) is affected by temperature, core clock frequency and voltage. Our results highlight how the underlying physical processes that govern transistor operation affect power efficiency. In particular, we show experimentally that GPU power consumption grows non-linearly with both temperature and supply voltage, as predicted by physical transistor models. We show lowering GPU supply voltage and increasing clock frequency while maintaining a low die temperature increases the power efficiency of an NVIDIA K20 GPU by up to 37-48% over default settings when running xGPU, a compute-bound code used in radio...

Price, D C; Barsdell, B R; Babich, R; Greenhill, L J

2014-01-01T23:59:59.000Z

28

Optimisation of voltage and frequency regulation in an isolated wind-driven six-phase self-excited induction generator  

Science Journals Connector (OSTI)

Abstract This paper presents a constant voltage operation of a Six-Phase Self-Excited Induction Generator (SPSEIG) driven by a fixed speed wind turbine using an Ant colony optimisation (ACO) technique to predict the behaviour of a the machine. In this paper, an attempt has been made to estimate the excitation capacitance requirements of a SPSEIG for maintaining rated terminal voltage and frequency. The range of capacitance variation required for maintaining constant terminal voltage while supplying a load of variable magnitude is evaluated. Analytical approaches, suitable for all the configurations of shunt capacitances such as variable excitation capacitance connected across (i) single three-phase winding set only and (ii) both the three-phase winding sets of an SPSEIG for operation as a simple shunt on no load and pure resistive load, are presented. The mathematical model developed is based on loop impedance method using graph theory. It is shown that the proposed technique is very effective and useful for making the SPSEIG feasible for remote areas with wind potential. The proposed approach is tested and compared with Genetic Algorithm (GA) and Fmincon technique.

A. Senthil Kumar; Josiah L. Munda

2014-01-01T23:59:59.000Z

29

PEV-Based Combined Frequency and Voltage Regulation for Smart Grid  

E-Print Network (OSTI)

by either adjusting supply or changing demand. While various demand side management programs have used benefit both users and utilities. Index Terms--Smart grid, plug-in electric vehicles, demand side management, reactive power compensation, ancillary ser- vices, frequency regulation, voltage regulation

Huang, Jianwei

30

An amorphous alloy core medium frequency magnetic-link for medium voltage photovoltaic inverters  

Science Journals Connector (OSTI)

The advanced magnetic materials with high saturation flux density and low specific core loss have led to the development of an efficient compact and lightweight multiple-input multiple-output medium frequency magnetic-link. It offers a new route to eliminate some critical limitations of recently proposed medium voltage photovoltaic inverters. In this paper a medium frequency magnetic-link is developed with Metglas amorphous alloy 2605S3A. The common magnetic-link generates isolated and balanced multiple DC supplies for all of the H-bridge inverter cells of the medium voltage inverter. The design and implementation of the prototype test platform and the experimental test results are analyzed and discussed. The medium frequency non-sinusoidal excitation electromagnetic characteristics of alloy 2605S3A are also compared with that of alloy 2605SA1. It is expected that the proposed new technology will have great potential for future renewable power generation systems and smart grid applications.

2014-01-01T23:59:59.000Z

31

LM231A/LM231/LM331A/LM331 Precision Voltage-to-Frequency Converters  

E-Print Network (OSTI)

LM231A/LM231/LM331A/LM331 Precision Voltage-to-Frequency Converters General Description The LM231/LM331 family of voltage-to-frequency converters are ideally suited for use in simple low, the LM231A/LM331A attain a new high level of accuracy versus temperature which could only be at- tained

Lanterman, Aaron

32

Trapping and Frequency Variability in Electron Acoustic Waves  

E-Print Network (OSTI)

Trapping and Frequency Variability in Electron Acoustic Waves C.F. Driscoll, F. Anderegg, D 92093 USA Abstract. Electron Acoustic Waves (EAWs) with a phase velocity less than twice the plasma Langmuir waves, and at large excitations resonance is observed over a broad range. Laser Induced

California at San Diego, University of

33

The Matrix Converter Drive Performance Under Abnormal Input Voltage Conditions  

E-Print Network (OSTI)

that generates variable magnitude variable frequency output voltage from the ac utility line. It has high power voltage disturbance related performance issues of the MC drive. Since the MC is a direct frequencyThe Matrix Converter Drive Performance Under Abnormal Input Voltage Conditions Jun-Koo Kang

Hava, Ahmet

34

Method for curing polymers using variable-frequency microwave heating  

DOE Patents (OSTI)

A method for curing polymers incorporating a variable frequency microwave furnace system designed to allow modulation of the frequency of the microwaves introduced into a furnace cavity is disclosed. By varying the frequency of the microwave signal, non-uniformities within the cavity are minimized, thereby achieving a more uniform cure throughout the workpiece. A directional coupler is provided for detecting the direction of a signal and further directing the signal depending on the detected direction. A first power meter is provided for measuring the power delivered to the microwave furnace. A second power meter detects the magnitude of reflected power. The furnace cavity may be adapted to be used to cure materials defining a continuous sheet or which require compressive forces during curing. 15 figs.

Lauf, R.J.; Bible, D.W.; Paulauskas, F.L.

1998-02-24T23:59:59.000Z

35

Method for curing polymers using variable-frequency microwave heating  

DOE Patents (OSTI)

A method for curing polymers (11) incorporating a variable frequency microwave furnace system (10) designed to allow modulation of the frequency of the microwaves introduced into a furnace cavity (34). By varying the frequency of the microwave signal, non-uniformities within the cavity (34) are minimized, thereby achieving a more uniform cure throughout the workpiece (36). A directional coupler (24) is provided for detecting the direction of a signal and further directing the signal depending on the detected direction. A first power meter (30) is provided for measuring the power delivered to the microwave furnace (32). A second power meter (26) detects the magnitude of reflected power. The furnace cavity (34) may be adapted to be used to cure materials defining a continuous sheet or which require compressive forces during curing.

Lauf, Robert J. (Oak Ridge, TN); Bible, Don W. (Clinton, TN); Paulauskas, Felix L. (Oak Ridge, TN)

1998-01-01T23:59:59.000Z

36

Variable current-voltage TPV device for use in a thermophotovoltaic energy conversion system  

DOE Patents (OSTI)

A front-side or back-side illuminated variable current-voltage thermophotovoltaic device comprises a support substrate; isolation layers disposed on the support substrate; a plurality of cells disposed on the isolation layers, each of the cells including a base layer and an emitter layer; an insulating member disposed between each of the cells configured to isolate each cell from adjacent cells; an ohmic contact configured to connect each cell to another cell in series; and a spectral control device disposed on top of the cells and/or on the bottom surface of the support substrate.

Charache, Greg W. (Clifton Park, NY); Baldasaro, Paul F. (Clifton Park, NY); Campbell, Brian C. (Scotia, NY)

2000-01-01T23:59:59.000Z

37

High efficiency pool filtering systems utilising variable frequency drives  

Science Journals Connector (OSTI)

Over 1 year, private swimming pools in Australia will typically consume 1680 GWh of electricity, producing 2130 kt of CO2. Redesigning a pool's filtration system and using it more efficiently can reduce the energy use, and hence the CO2 production, by a significant amount. This paper describes experimental measurements carried out on a new design of pool pump system. Initial experiments using a variable frequency drive (VFD) with a standard, single phase pump/motor system have achieved energy savings of 40%. Utilising a VFD and a three phase pump/motor energy savings of 61% have been achieved, without degrading the system performance.

Z. Hameiri; T. Spooner; A.B. Sproul

2009-01-01T23:59:59.000Z

38

Efficient Energy Management: Is Variable Frequency Drives the Solution  

Science Journals Connector (OSTI)

Abstract Over the last few years the cost of power electricity has increased significantly. Researchers and manufacturers of electrical goods have been trying to find ways to minimize the use of power electricity while maintaining the efficiency of electrical equipments. To provide efficient energy management for today's market, manufacturers are now turning to a technology known as variable frequency drives (VFDs). \\{VFDs\\} are being used for various equipments ranging from small electrical appliances to the largest of mine mill drives and compressors. Household air conditioning compressors, for example, are not short of running on VFD technology. This concept paper will discuss the alternative use of this energy.

Nasir Khalid

2014-01-01T23:59:59.000Z

39

Radio-Frequency Interference (RFI) From Extra-High-Voltage (EHV) Transmission Lines  

E-Print Network (OSTI)

discharges are a design issue. Extra-high-voltage (EHV) transmission lines have operating voltages of 345 kV building a 345-kV transmission line from Red Hill, NM to Deming, NM which would run east along US60 to its with respect to radio noise: (1) lines with voltages below 70 kV and (2) lines with voltages above 110 kV

Ellingson, Steven W.

40

Breaking the ice: de-icing power transmission lines with high-frequency, high-voltage excitation  

E-Print Network (OSTI)

Breaking the ice: de-icing power transmission lines with high-frequency, high-voltage excitation of this work in other works must be obtained from the IEEE. #12;CING OF POWER TRANSMISSION lines during winter that applies 33-kV, 100-kHz power. TheoverallsystemisillustratedinFigure1.Itcouldbede- ployed in two different

Note: This page contains sample records for the topic "frequency variable voltage" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


41

Radio-frequency powered glow discharge device and method with high voltage interface  

DOE Patents (OSTI)

A high voltage accelerating potential, which is supplied by a high voltage direct current power supply, is applied to the electrically conducting interior wall of an RF powered glow discharge cell. The RF power supply desirably is electrically grounded, and the conductor carrying the RF power to the sample held by the probe is desirably shielded completely excepting only the conductor's terminal point of contact with the sample. The high voltage DC accelerating potential is not supplied to the sample. A high voltage capacitance is electrically connected in series between the sample on the one hand and the RF power supply and an impedance matching network on the other hand. The high voltage capacitance isolates the high DC voltage from the RF electronics, while the RF potential is passed across the high voltage capacitance to the plasma. An inductor protects at least the RF power supply, and desirably the impedance matching network as well, from a short that might occur across the high voltage capacitance. The discharge cell and the probe which holds the sample are configured and disposed to prevent the probe's components, which are maintained at ground potential, from bridging between the relatively low vacuum region in communication with the glow discharge maintained within the cell on the one hand, and the relatively high vacuum region surrounding the probe and cell on the other hand. The probe and cell also are configured and disposed to prevent the probe's components from electrically shorting the cell's components. 11 figures.

Duckworth, D.C.; Marcus, R.K.; Donohue, D.L.; Lewis, T.A.

1994-06-28T23:59:59.000Z

42

Analysis and Simulation of Mechanical Trains Driven by Variable Frequency Drive Systems.  

E-Print Network (OSTI)

??Induction motors and Variable Frequency Drives (VFDs) are widely used in industry to drive machinery trains. However, some mechanical trains driven by VFD-motor systems have… (more)

Han, Xu

2012-01-01T23:59:59.000Z

43

Variable optical attenuator with a polymer-stabilized dual-frequency liquid crystal  

E-Print Network (OSTI)

Variable optical attenuator with a polymer-stabilized dual-frequency liquid crystal Yung-Hsun Wu. For the DFLC-based homogeneous cell, we use a low- frequency 1 kHz electric field to drive the VOA and a high-frequency, Xiao Liang, Yan-Qing Lu, Fang Du, Yi-Hsin Lin, and Shin-Tson Wu A transmission-type variable optical

Wu, Shin-Tson

44

Challenges and opportunities for multi-functional oxide thin films for voltage tunable radio frequency/microwave components  

SciTech Connect

There has been significant progress on the fundamental science and technological applications of complex oxides and multiferroics. Among complex oxide thin films, barium strontium titanate (BST) has become the material of choice for room-temperature-based voltage-tunable dielectric thin films, due to its large dielectric tunability and low microwave loss at room temperature. BST thin film varactor technology based reconfigurable radio frequency (RF)/microwave components have been demonstrated with the potential to lower the size, weight, and power needs of a future generation of communication and radar systems. Low-power multiferroic devices have also been recently demonstrated. Strong magneto-electric coupling has also been demonstrated in different multiferroic heterostructures, which show giant voltage control of the ferromagnetic resonance frequency of more than two octaves. This manuscript reviews recent advances in the processing, and application development for the complex oxides and multiferroics, with the focus on voltage tunable RF/microwave components. The over-arching goal of this review is to provide a synopsis of the current state-of the-art of complex oxide and multiferroic thin film materials and devices, identify technical issues and technical challenges that need to be overcome for successful insertion of the technology for both military and commercial applications, and provide mitigation strategies to address these technical challenges.

Subramanyam, Guru, E-mail: gsubramanyam1@udayton.edu [Department of Electrical and Computer Engineering, University of Dayton, Dayton, Ohio 45469 (United States); Cole, M. W., E-mail: melanie.w.cole.civ@mail.mil [U.S. Army Research Laboratory, Weapons and Materials Research Directorate, Aberdeen Proving Ground, Maryland 21005 (United States); Sun, Nian X. [Department of Electrical and Computer Engineering, Northeastern University, Boston, Massachusetts 02115 (United States); Kalkur, Thottam S. [Department of Electrical and Computer Engineering, University of Colorado, Colorado Springs, Colorado 80918 (United States); Sbrockey, Nick M.; Tompa, Gary S. [Structured Materials Industries, Inc., Piscataway, New Jersey 08854 (United States); Guo, Xiaomei [Boston Applied Technologies, Inc., Woburn, Massachusetts 01801 (United States); Chen, Chonglin [Department of Physics and Astronomy, University of Texas, San Antonio, Texas 78249 (United States); Alpay, S. P.; Rossetti, G. A. [Institute of Materials Science and Materials Science and Engineering Program, University of Connecticut, Storrs, Connecticut 06269 (United States); Dayal, Kaushik [Mechanics, Materials and Computing, Civil and Environmental Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213 (United States); Chen, Long-Qing [Department of Materials Science and Engineering, Penn State University, University Park, Pennsylvania 16802 (United States); Schlom, Darrell G. [Department of Materials Science and Engineering, Cornell University, Ithaca, New York 14853 (United States); Kavli Institute at Cornell for Nanoscale Science, Ithaca, New York 14853 (United States)

2013-11-21T23:59:59.000Z

45

A review on sensorless techniques for sustainable reliablity and efficient variable frequency drives of induction motors  

Science Journals Connector (OSTI)

Abstract Variable frequency drives (VFDs) can provide reliable dynamic systems and significant savings in energy usage and costs of the induction motors (IMs). Sensorless controlled IM drives have advantages in terms of efficiency enhancement and energy savings for critical applications such as electric vehicles, high performance machine tools, fans, compressors, etc. IM drives without having speed sensors or optical encoders mounted at the motor shaft are attractive because of their lower cost and higher reliability. When mechanical speed sensor is removed, the rotor speed information is estimated using the measured quantities of stator voltages and currents at the IM terminals. This paper highlights the sensorless techniques applied to the IM drives for sustainable reliability and energy savings. Overview on the IM mathematical model is briefly summarized to establish a physical basis for the sensorless schemes used. Further, the different types of IM-VFDs are presented in the paper. The main focus of this review is on the sensorless estimation techniques which are being applied to make IM-VFDs more effective during wide speed operations including very-high and very-low speed regions.

Ibrahim M. Alsofyani; N.R.N. Idris

2013-01-01T23:59:59.000Z

46

Low-Variation 1 MHz Clock Generator,High Sensitivity Linear Voltage-to-Frequency Converter,and High-PSR Bias Circuit for NTSC SYNC Separation.  

E-Print Network (OSTI)

??This thesis includes three topics. The first topic is a low-variation 1 MHz clock generator. The second one is a high sensitivity linear voltage-to-frequency converter.… (more)

Lee, Tzung-Je

2004-01-01T23:59:59.000Z

47

A novel study for constant voltage and frequency operation of self-excited short-shunt induction generator  

Science Journals Connector (OSTI)

This paper presents an analytical technique for selecting the optimal shunt and series capacitances required for maintaining constant load voltage and frequency of a self excited short shunt induction generator (SESSIG). The study investigates the performance of the SESSIG at different operating conditions, such as speed of the prime mover, load impedance and load power factor. The required capacitances have been determined using two second order non-linear equations based on the steady state equivalent circuit model, instead of the high order non-linear equations in the literatures. The capacitance values obtained by the proposed technique have been verified experimentally to confirm the validity and the accuracy of the proposed technique.

H.H. Hanafy; S.A. Zaid; A.M. Gesraha; M.M. Abd-Elaziz

2012-01-01T23:59:59.000Z

48

A very high frequency CMOS Variable Gain Amplifier  

E-Print Network (OSTI)

of the VGA output signal . . . . . . . . . 80 Bandwidth with different frequency compensation circuits bias current at 22dB gain setting. . . 84 XIV VGA comparison . . . 88 LIST OF FIGURE FIGURE I 2", 3 and 4'" order sigma-delta modulator SNR vs. input... level . . . . Page 2 Block diagram of a direct conversion receiver. 3 Single transistor transconductor 4 Differential pair 5 Source degeneration amplifier. 6 Four-quadrant multiplier basic architectures . . . . . . . . 10 7 Multiplier as a...

Tan, Siang Tong

2012-06-07T23:59:59.000Z

49

Variable Frequency AC Drives for Cooling Tower Energy Efficiency  

E-Print Network (OSTI)

and economics. Automatic fan speed control by sensing cold water temperature is the economic essence of the application of adjustable frequency power to A-C fan motors. 2.2 Cell Partitions In some multi-cell mechanical-draft cooling towers, the isolation... of individual cell air streams is ineffective due to one or more of the following: --Partitions are missing. --Partitions are incomplete. This condition results in temperature control problems. For example, if constant CWT is desired, and no means...

Corey, R. W.

1982-01-01T23:59:59.000Z

50

Vacuum electron acceleration by using two variable frequency laser pulses  

SciTech Connect

A method is proposed for producing a relativistic electron bunch in vacuum via direct acceleration by using two frequency-chirped laser pulses. We consider the linearly polarized frequency-chiped Hermit-Gaussian 0, 0 mode lasers with linear chirp in which the local frequency varies linearly in time and space. Electron motion is investigated through a numerical simulation using a three-dimensional particle trajectory code in which the relativistic Newton's equations of motion with corresponding Lorentz force are solved. Two oblique laser pulses with proper chirp parameters and propagation angles are used for the electron acceleration along the z-axis. In this way, an electron initially at rest located at the origin could achieve high energy, ?=319 with the scattering angle of 1.02{sup ?} with respect to the z-axis. Moreover, the acceleration of an electron in different initial positions on each coordinate axis is investigated. It was found that this mechanism has the capability of producing high energy electron microbunches with low scattering angles. The energy gain of an electron initially located at some regions on each axis could be greatly enhanced compared to the single pulse acceleration. Furthermore, the scattering angle will be lowered compared to the acceleration by using laser pulses propagating along the z-axis.

Saberi, H.; Maraghechi, B. [Department of Physics, Amirkabir University of Technology, 15875-4413 Tehran (Iran, Islamic Republic of)] [Department of Physics, Amirkabir University of Technology, 15875-4413 Tehran (Iran, Islamic Republic of)

2013-12-15T23:59:59.000Z

51

A High-Frequency Resonant Inverter Topology With Low-Voltage Stress  

E-Print Network (OSTI)

This paper presents a new switched-mode resonant inverter, which we term the inverter, that is well suited to operation at very high frequencies and to rapid on/off control. Features of this inverter topology include low ...

Rivas, Juan M.

52

Analysis and Simulation of Mechanical Trains Driven by Variable Frequency Drive Systems  

E-Print Network (OSTI)

Induction motors and Variable Frequency Drives (VFDs) are widely used in industry to drive machinery trains. However, some mechanical trains driven by VFD-motor systems have encountered torsional vibration problems. This vibration can induce large...

Han, Xu

2012-02-14T23:59:59.000Z

53

High-voltage nanosecond pulses in a low-pressure radio-frequency discharge  

Science Journals Connector (OSTI)

An influence of a high-voltage (3–17 kV) 20 ns pulse on a weakly-ionized low-pressure (0.1–10 Pa) capacitively coupled radiofrequency (RF) argon plasma is studied experimentally. The plasma evolution after pulse exhibits two characteristic regimes: a bright flash, occurring within 100 ns after the pulse (when the discharge emission increases by 2–3 orders of magnitude over the steady-state level), and a dark phase, lasting a few hundreds ?s (when the intensity of the discharge emission drops significantly below the steady-state level). The electron density increases during the flash and remains very large at the dark phase. 1D3V particle-in-cell simulations qualitatively reproduce both regimes and allow for detailed analysis of the underlying mechanisms. It is found that the high-voltage nanosecond pulse is capable of removing a significant fraction of plasma electrons out of the discharge gap, and that the flash is the result of the excitation of gas atoms, triggered by residual electrons accelerated in the electric field of immobile bulk ions. The secondary emission from the electrodes due to vacuum UV radiation plays an important role at this stage. High-density plasma generated during the flash provides efficient screening of the RF field (which sustains the steady-state plasma). This leads to the electron cooling and, hence, onset of the dark phase.

M. Y. Pustylnik; L. Hou; A. V. Ivlev; L. M. Vasilyak; L. Couëdel; H. M. Thomas; G. E. Morfill; V. E. Fortov

2013-06-10T23:59:59.000Z

54

Fine-Grained Dynamic Voltage and Frequency Scaling for Precise Energy and Performance  

E-Print Network (OSTI)

Monitoring Unit (PMU) ! Proposed Fine-grained DVFS Policy ! Experimental Results ! Conclusion #12;2 Energy (memory work) " T = Tonchip + Toffchip ! Tonchip : varies with the CPU frequency " Stalls due to data Monitoring Unit (PMU) ! PMU on the XScale processor chip can report up to 20 different dynamic events during

Pedram, Massoud

55

Experimental investigation of dielectric barrier discharge plasma actuators driven by repetitive high-voltage nanosecond pulses with dc or low frequency sinusoidal bias  

SciTech Connect

Experimental studies were conducted of a flow induced in an initially quiescent room air by a single asymmetric dielectric barrier discharge driven by voltage waveforms consisting of repetitive nanosecond high-voltage pulses superimposed on dc or alternating sinusoidal or square-wave bias voltage. To characterize the pulses and to optimize their matching to the plasma, a numerical code for short pulse calculations with an arbitrary impedance load was developed. A new approach for nonintrusive diagnostics of plasma actuator induced flows in quiescent gas was proposed, consisting of three elements coupled together: the schlieren technique, burst mode of plasma actuator operation, and two-dimensional numerical fluid modeling. The force and heating rate calculated by a plasma model was used as an input to two-dimensional viscous flow solver to predict the time-dependent dielectric barrier discharge induced flow field. This approach allowed us to restore the entire two-dimensional unsteady plasma induced flow pattern as well as characteristics of the plasma induced force. Both the experiments and computations showed the same vortex flow structures induced by the actuator. Parametric studies of the vortices at different bias voltages, pulse polarities, peak pulse voltages, and pulse repetition rates were conducted experimentally. The significance of charge buildup on the dielectric surface was demonstrated. The charge buildup decreases the effective electric field in the plasma and reduces the plasma actuator performance. The accumulated surface charge can be removed by switching the bias polarity, which leads to a newly proposed voltage waveform consisting of high-voltage nanosecond repetitive pulses superimposed on a high-voltage low frequency sinusoidal voltage. Advantages of the new voltage waveform were demonstrated experimentally.

Opaits, Dmitry F.; Likhanskii, Alexandre V.; Neretti, Gabriele; Zaidi, Sohail; Shneider, Mikhail N.; Miles, Richard B. [Mechanical and Aerospace Engineering, Princeton University, Princeton, New Jersey 08544 (United States); Macheret, Sergey O. [Lockheed Martin Aeronautics Company, Palmdale, California 93599 (United States)

2008-08-15T23:59:59.000Z

56

Application of multi-variable control for automatic frequency controller of HVDC transmission system  

SciTech Connect

In an HVDC transmission system that links two ac power systems, the automatic frequency controller (AFC) calculates power to be interchanged between the two ac systems according to their frequencies thereby improving the frequency characteristics of the two power systems. This paper introduces a newly developed dc AFC system, which applies a multi-variable control to the dc system-based frequency control. It is capable of controlling the frequencies of the two ac systems optimally while maintaining their stability. This system was developed for one of Japan's HVDC transmission facilities and produced good results in a combined test using a power system simulator. The field installation will be completed in March 1993, when the AFC system will enter service.

Sanpei, Masatoshi (Electric Power Development Co., Tokyo (Japan)); Kakehi, Atsuyuki; Takeda, Hideo (Toshiba Corp., Tokyo (Japan))

1994-04-01T23:59:59.000Z

57

Electro-Thermal Dynamics and the Effects of Generalized Discontinuous Pulse Width Modulation Algorithms on High Performance Variable Frequency Drives.  

E-Print Network (OSTI)

??This thesis is concerned with issues observed with the variable frequency drive, VFD, traction inverter used in the Buckeye Bullet 3 as it performed during… (more)

Krohn, Austin Bengoechea

2014-01-01T23:59:59.000Z

58

Extinction risk and eco-evolutionary dynamics in a variable environment with increasing frequency of extreme events  

Science Journals Connector (OSTI)

...35] found that in a variable environment extinction...accompanied by an increased frequency of climate and point...accompanied by an increased frequency of climate and point...a continuous climate variable, such as mean of summer...climate trend mostly drives the shift of the phenotype...

2014-01-01T23:59:59.000Z

59

The variability of high-frequency acoustic backscatter from the region near the sea surface  

Science Journals Connector (OSTI)

The temporal variability of acoustic backscattering from the region near the sea surface is examined for frequencies in the 30–70 kHz range. A variance spectrum of the scattering strength exhibits effects associated with three different processes. Below about 0.1 Hz the spectrum contains a large contribution associated with temporal variations in the advection of bubble clouds through the measurement volume by large-scale processes. At high frequencies the spectrum asymptotes to a level characteristic of a Gaussian backscatteredpressure field from randomly moving bubbles within the scattering volume. The overall variability is treated as a slow modulation of this Gaussian process by larger-scale processes and a probability density function is derived for the scattering strength using Bayes’ theorem. Finally in some cases the spectrum exhibits a peak at the frequency of the dominant surface waves. Attempts to compute coherence functions between the backscattered acoustic power and surface wave orbital velocities measured by a microwave system observing the same spot as the acoustic system resulted in very low values. This leads to the belief that the wave-induced peak in the acoustic backscatter variance spectrum is caused by highly nonlinear processes. A time series of acoustic backscatter from a vertically pointing system confirms the existence of this modulation at the dominant wave frequency and also suggests its nonlinear character.

Peter H. Dahl; William J. Plant

1997-01-01T23:59:59.000Z

60

Onset of chaos and dc current-voltage characteristics of rf-driven Josephson junctions in the low-frequency regime  

Science Journals Connector (OSTI)

A comprehensive picture of the dc current-voltage (I-V) characteristics of rf-driven Josephson junctions in the low-frequency regime is presented. The boundary of the low-frequency regime is roughly defined by the junction characteristic frequency for overdamped junctions, and by the inverse of the junction damping time for underdamped junctions. An adiabatic model valid for the low-frequency regime is used to describe the overall shapes of the I-V curves, which is in good agreement with both the numerical simulations and the experimental results. For underdamped junctions, the Shapiro steps are the prominent features on the I-V curves if the rf frequency is sufficiently below the boundary. As the rf frequency is increased towards the boundary, large negatively-going tails on top of the Shapiro steps are observed both experimentally and numerically. Numerical simulations using the resistively- and capacitively-shunted-junction model (RCSJ model) reveal that the negatively-going tail is a signature of the low-frequency boundary of the junction chaotic regime. With use of the adiabatic model and the existence of plasma oscillations for underdamped junctions, the onset of chaos and its effect on the Shapiro steps can be fully explained. The high-frequency limit of the adiabatic model and the chaotic behavior of the Josephson junctions beyond the low-frequency regime are also briefly discussed.

C. C. Chi and C. Vanneste

1990-12-01T23:59:59.000Z

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61

Connecting Renewables Directly to the Grid: Resilient Multi-Terminal HVDC Networks with High-Voltage High-Frequency Electronics  

SciTech Connect

GENI Project: GE is developing electricity transmission hardware that could connect distributed renewable energy sources, like wind farms, directly to the grid—eliminating the need to feed the energy generated through intermediate power conversion stations before they enter the grid. GE is using the advanced semiconductor material silicon carbide (SiC) to conduct electricity through its transmission hardware because SiC can operate at higher voltage levels than semiconductors made out of other materials. This high-voltage capability is important because electricity must be converted to high-voltage levels before it can be sent along the grid’s network of transmission lines. Power companies do this because less electricity is lost along the lines when the voltage is high.

None

2012-01-23T23:59:59.000Z

62

Running time variability and resource allocation : a data-driven analysis of high-frequency bus operations  

E-Print Network (OSTI)

Running time variability is one of the most important factors determining service quality and operating cost of high-frequency bus transit. This research aims to improve performance analysis tools currently used in the bus ...

Sánchez-Martínez, Gabriel Eduardo

2013-01-01T23:59:59.000Z

63

Optical voltage reference  

DOE Patents (OSTI)

An optical voltage reference for providing an alternative to a battery source is described. The optical reference apparatus provides a temperature stable, high precision, isolated voltage reference through the use of optical isolation techniques to eliminate current and impedance coupling errors. Pulse rate frequency modulation is employed to eliminate errors in the optical transmission link while phase-lock feedback is employed to stabilize the frequency to voltage transfer function. 2 figures.

Rankin, R.; Kotter, D.

1994-04-26T23:59:59.000Z

64

Effect of radio-frequency bias voltage on the optical and structural properties of hydrogenated amorphous silicon carbide  

SciTech Connect

Hydrogenated amorphous silicon carbide (a-Si{sub 1{minus}x}C{sub x}:H) films have been deposited using the electron cyclotron resonance chemical vapor deposition process under varying negative rf-bias voltage at the substrate. The optical and structural properties of these films are characterized using Rutherford backscattering spectroscopy, transmittance/reflectance spectrophotometry, photothermal deflection spectroscopy, Fourier transform infrared absorption, Raman scattering, and room temperature photoluminescence (PL). These films deposited using a gas mixture of silane, methane, and hydrogen at a constant gas flow ratio showed a slight increase in the carbon fraction x, but very obvious structural transformation, at increasing rf induced bias voltage from {minus}20 to {minus}120 V. Near stoichiometric a-Si{sub 1{minus}x}C{sub x}:H films with a carbon fraction x of almost 0.5 are achieved at low bias voltage range from {minus}20 to {minus}60 V. Visible PL with relatively low efficiency can be observed from such films at room temperature. For larger bias voltages from {minus}80 to {minus}120 V, slightly C-rich a-Si{sub 1{minus}x}C{sub x}:H films (x{gt}0.5) with larger optical gaps are obtained. These films have relatively higher PL efficiency, and the relative quantum efficiency was also found to depend strongly on the optical gap. Structurally, it was found that there is an increase in the hydrogen content and carbon sp{sup 2} bonding in the films at larger bias voltages. The latter leads to an increase in the disorder in the films. The linear relationship observed between the Urbach energy E{sub 0} and B factor in the Tauc equation suggests that the local defects related to microstructural disorder resulting from alloying with carbon dominate the overall defect structure of the films. Substrate biasing is noted to be crucial for the formation of Si{endash}C bonds, as deduced from the Raman scattering results. {copyright} 2001 American Institute of Physics.

Cui, J.; Rusli; Yoon, S. F.; Teo, E. J.; Yu, M. B.; Chew, K.; Ahn, J.; Zhang, Q.; Osipowicz, T.; Watt, F.

2001-06-01T23:59:59.000Z

65

Soft switched high frequency ac-link converter  

E-Print Network (OSTI)

Variable frequency drives typically have employed dc voltage or current links for power distribution between the input and output converters and as a means to temporarily store energy. The dc link based power conversion systems have several inherent...

Balakrishnan, Anand Kumar

2009-05-15T23:59:59.000Z

66

Dead-Space Theory Predictions of Excess-Noise Factor, Breakdown Voltage, and Frequency Response for Thin Avalanche Photodiodes  

E-Print Network (OSTI)

for Thin Avalanche Photodiodes Majeed M. Hayat°", Mohammad A. Sa1eh', Ohhyun Kwonc, Bahaa E. A. Sale width. Keywords: Avalanche photodiode, dead space, impact ionization, excess noise factor, avalanche breakdown down, frequency response. 1 Introduction It is well known that for avalanche photodiodes (APDs

Teich, Malvin C.

67

A Voltage Controlled Oscillator for a Phase-Locked Loop Frequency Synthesizer in a Silicon-on-Sapphire Process  

E-Print Network (OSTI)

in a Low-Temperature Co-fired Ceramic (LTCC) Multi-Chip Module. The integrated circuit technology chosen for the Phase-Locked Loop Frequency Synthesizer portion of the telemetry transmitter was a 0.25 um CMOS process that utilizes a sapphire substrate...

Garrison, Sean Michael

2009-05-22T23:59:59.000Z

68

The bi-variate frequency distribution of two concurrent climatic variables: a study of temperature and dew point  

E-Print Network (OSTI)

for calculation of joint-event probabilities from the bi-variate normal distribution as follows: X and Y are random variables following a bi- variate normal distribution with zero means, unit variances and correlation coefficient p. Then: Pr [X & h, Y 2 k) = L... 1956-1960. Despite many useful applications, the calculation of frequencies or probabilities for specified events is somewhat limited to the class selections of the variables chosen for the study. Moreover, relative humidity is not a good indicator...

Zeitler, Jon William

1991-01-01T23:59:59.000Z

69

Effect on energy use and greenhouse microclimate through fan motor control by variable frequency drives  

Science Journals Connector (OSTI)

A comparison was conducted between ON–OFF and variable frequency drive (VFD) systems to control greenhouse ventilation fans. The study aimed to determine the effect of each system on the energy consumption and resulting greenhouse microclimate. The experiments were conducted in a commercial size greenhouse in which pepper was grown. To check the performance of the fan that was controlled by a VFD system, it was installed in a test facility and operated under several rotation speeds. At each speed of rotation, the static pressure on the fan was changed and parameters, such as electricity consumption and air flow rate, were measured. Reducing the fan speed with the VFD system resulted in reductions in the air flow rate through the greenhouse and energy consumption, the latter being much more significant. The study showed that VFD control can reduce electricity consumption compared with ON–OFF operation by an amount that depends on the weather. In the present study, the average energy consumption with the VFD control system over a period of one month, was about 0.64 of that with an ON–OFF system. The average greenhouse daily air temperatures and humidity ratios obtained with each control system between 0700 and 1800 were nearly equal during that month. The results obtained in the greenhouse further show that the VFD system has a greater potential than the ON–OFF to reduce the range of amplitude variations in the air temperature and humidity ratio within the greenhouse.

Meir Teitel; Yun Zhao; Moti Barak; Eli Bar-lev; David Shmuel

2004-01-01T23:59:59.000Z

70

Variable frequency drives for MSF desalination plant and associated pumping stations  

Science Journals Connector (OSTI)

Power Electronic Variable Frequency Drives (VFD) are a well proven, reliable and cost efficient solution to ensure precise control of torque and speed of electrically driven rotating machines (such as pumps, compressors, fans, extruders etc.) in a wide range of industrial process. For the purpose of pumps applications, if compared to conventional mechanical flow regulation systems (vanes, gearbox, hydraulic coupling etc.) VFD provides the advantages of more efficient energy management as well as better accuracy and flexibility in process control. Latest technologies in silicon power devices, microprocessors and software development allowed remarkable improvements in performances, reliability and cost reduction; as a consequence energy savings due to VFD use are ensuring investment pay back in a very short time. After a quick summary about basic concepts on VFD for fluid flow control and a short description of different VFD’s topologies presently available, special attention is focused on a recent application for pump in a MSF desalination, as well as in other applications in pumping stations for water transmission systems associated to desalination plants.

Roberto Camoirano; Giuseppe Dellepiane

2005-01-01T23:59:59.000Z

71

Field Verification of Energy and Demand Savings of Two Injection Molding Machines Retrofitted with Variable Frequency Drives  

E-Print Network (OSTI)

Detailed field measurements of energy consumption (kWh) and demand (kW) are conducted on two injection molding machines (IMMs) used in a typical plastic manufacturing facility in the San Francisco Bay Area, with/without Variable Frequency Drives...

Liou, S. P.; Aguiar, D.

72

Comparing Two Types of Magnetically- Coupled Adjustable Speed Drives with Variable Frequency Drives in Pump and Fan Applications  

E-Print Network (OSTI)

This paper presents the results from laboratory tests on MagnaDrive Corporations fixed-magnet magnetically-coupled adjustable speed drive (MC-ASD) and Coyote Electronics electromagnetic MC-ASD as compared to a typical variable frequency drive (VFD...

Anderson, K. J.; Chvala, W. D.

73

Use of Frequency Response Metrics to Assess the Planning and Operating Requirements for Reliable Integration of Variable Renewable Generation  

SciTech Connect

An interconnected electric power system is a complex system that must be operated within a safe frequency range in order to reliably maintain the instantaneous balance between generation and load. This is accomplished by ensuring that adequate resources are available to respond to expected and unexpected imbalances and restoring frequency to its scheduled value in order to ensure uninterrupted electric service to customers. Electrical systems must be flexible enough to reliably operate under a variety of"change" scenarios. System planners and operators must understand how other parts of the system change in response to the initial change, and need tools to manage such changes to ensure reliable operation within the scheduled frequency range. This report presents a systematic approach to identifying metrics that are useful for operating and planning a reliable system with increased amounts of variable renewable generation which builds on existing industry practices for frequency control after unexpected loss of a large amount of generation. The report introduces a set of metrics or tools for measuring the adequacy of frequency response within an interconnection. Based on the concept of the frequency nadir, these metrics take advantage of new information gathering and processing capabilities that system operators are developing for wide-area situational awareness. Primary frequency response is the leading metric that will be used by this report to assess the adequacy of primary frequency control reserves necessary to ensure reliable operation. It measures what is needed to arrest frequency decline (i.e., to establish frequency nadir) at a frequency higher than the highest set point for under-frequency load shedding within an interconnection. These metrics can be used to guide the reliable operation of an interconnection under changing circumstances.

Eto, Joseph H.; Undrill, John; Mackin, Peter; Daschmans, Ron; Williams, Ben; Haney, Brian; Hunt, Randall; Ellis, Jeff; Illian, Howard; Martinez, Carlos; O'Malley, Mark; Coughlin, Katie; LaCommare, Kristina Hamachi

2010-12-20T23:59:59.000Z

74

Energy saving in agricultural buildings through fan motor control by variable frequency drives  

Science Journals Connector (OSTI)

A comparison was conducted between ON–OFF and variable frequency drive (VFD) systems to control ventilation fans of greenhouses and poultry houses. The study aimed to determine the effect of each system on the energy consumption and resulting microclimate within the houses. The experiments were carried out in a commercial-size greenhouse in which pepper was grown and in commercial poultry houses. Reducing the fan speed with the VFD system resulted in reductions in the airflow rate through the houses and energy consumption, the latter being much more significant. The study showed that VFD control can reduce electricity consumption compared with ON–OFF operation. In the present study, the average energy consumption with the VFD control system was about 0.64 and 0.75 of that with an ON–OFF system in the greenhouse and poultry houses, respectively. The average greenhouse daily air temperatures and humidity ratios obtained with each control system between 07:00 and 18:00 were nearly equal. The results obtained in the greenhouse further showed that the VFD system has a greater potential than the ON–OFF, to reduce the range of amplitude variations in the air temperature and humidity ratio within the greenhouse. The average air temperatures over day and night, in the poultry houses, with each control system were nearly equal. The relative humidity, however, was slightly lower with VFD than with ON–OFF. Reductions in the range of amplitude variations of the air temperature and humidity were also observed in the poultry houses.

Meir Teitel; Asher Levi; Yun Zhao; Moti Barak; Eli Bar-lev; David Shmuel

2008-01-01T23:59:59.000Z

75

A BIST Technique for RF Voltage-Controlled Oscillators  

Science Journals Connector (OSTI)

A built-in self-test (BIST) architecture is proposed for voltage-controlled oscillators (VCO) operating at multigigahertz frequencies. By utilizing a frequency divider and a frequency-to-voltage converter (FVC), the output frequency and tuning range ...

Hsieh-Hung Hsieh; Yen-Chih Huang; Liang-Hung Lu; Guo-Wei Huang

2007-10-01T23:59:59.000Z

76

Techno-economic feasibility study of providing variable frequency drive for high pressure pump, SWRO plant at NDDP, Kalpakkam  

Science Journals Connector (OSTI)

The cost of product water is a key factor in determination of acceptability of any desalination system and plant. In case of Sea Water Reverse Osmosis plants, most of the energy consumed is in the form of electricity. The High Pressure Pump (HPP) is the single major energy consuming equipment with a share of above 75%. Hence reduction in energy consumed by HPP will have a substantial effect on the overall energy consumption. The high starting torque requirement of high pressure pump results in increased acceleration time of the motor which subsequently increases the strain on the upstream electrical system from motor feeder to transformer. Provision of a Variable Frequency Drive can be a solution for both the above problems. This paper studies the techno-economic feasibility of providing variable frequency drive for HPP motor at NDDP, Kalpakkam.

R. Nagaraj; V. Murugan; Ashok Y. Dangore; K.L. Thalor; S. Prabakar; V.K. Srivastava; P.K. Tewari

2010-01-01T23:59:59.000Z

77

High-Frequency Variability in Hurricane Power Dissipation and Its Relationship to Global Temperature  

Science Journals Connector (OSTI)

The power dissipation of Atlantic tropical cyclones has risen dramatically during the last decades and the increase is correlated with an increase in the underlying sea surface temperature (SST) at low (decadal) frequencies. Because of the large ...

James B. Elsner; Anastasios A. Tsonis; Thomas H. Jagger

2006-06-01T23:59:59.000Z

78

Spatial and temporal variability of the frequency of extreme daily rainfall regime in the La Plata Basin during the 20th century  

Science Journals Connector (OSTI)

We analyzed trends, interdecadal variability, and the quantification of the changes in the frequency of daily rainfall for two thresholds: 0.1 mm and percentile 75th, using high quality daily series from 52 st...

Olga C. Penalba; Federico A. Robledo

2010-02-01T23:59:59.000Z

79

An AChBKr315M2BU3 induction variable-frequency electric motor with a squirrel-cage rotor  

Science Journals Connector (OSTI)

Information about a variable-frequency electric motor designed and manufactured by OAO NIPTIEM is presented. The motor is intended for use as a starter motor for the GTU-8 gas turbine power...

M. F. Zapadnya; O. V. Martynov; S. V. Piskunov…

2007-06-01T23:59:59.000Z

80

A study of wind variability in the lower troposphere through power spectrum analysis at mesoscale frequencies  

E-Print Network (OSTI)

on the theoretical and practical application of the analysis method comes directly from this reference. B. Fundamental Assum tions of Power S ectrum Theor Consider a function of time X(t), such as wind speed, which is generated by a random process. Then the value... of the function X(t) at any particular point in time is a random variable. This random process may or may not have a Gaussian or normal distribution but it is a fundamental assumption (at least in the development of the theory) that the random process...

Cornett, John Sheldon

1966-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "frequency variable voltage" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


81

Control of Analyte Electrolysis in Electrospray Ionization Mass Spectrometry Using Repetitively Pulsed High Voltage  

SciTech Connect

Analyte electrolysis using a repetitively pulsed high voltage ion source was investigated and compared to that using a regular, continuously operating direct current high voltage ion source in electrospray ionization mass spectrometry. The extent of analyte electrolysis was explored as a function of the length and frequency of the high voltage pulse using the model compound reserpine in positive ion mode. Using +5 kV as the maximum high voltage amplitude, reserpine was oxidized to its 2, 4, 6 and 8-electron oxidation products when direct current high voltage was employed. In contrast, when using a pulsed high voltage, oxidation of reserpine was eliminated by employing the appropriate high voltage pulse length and frequency. This effect was caused by inefficient mass transport of the analyte to the electrode surface during the duration of the high voltage pulse and the subsequent relaxation of the emitter electrode/ electrolyte interface during the time period when the high voltage was turned off. This mode of ESI source operation allows for analyte electrolysis to be quickly and simply switched on or off electronically via a change in voltage pulse variables.

Kertesz, Vilmos [ORNL; Van Berkel, Gary J [ORNL

2011-01-01T23:59:59.000Z

82

Method and apparatus for monitoring the rotating frequency of de-energized induction motors  

DOE Patents (OSTI)

The rotational speed of a coasting induction motor is measured by sensing e residual electrical voltages at the power terminals of the motor, thus eliminating the need for conventional tachometer equipment, additional mechanical components or modifications to the induction motor itself. The power terminal voltage signal is detected and transformed into a DC voltage proportional to the frequency of the signal. This DC voltage can be input to the control system of a variable frequency motor controller to regulate the output characteristics thereof relative to the speed of the coasting motor. 6 figs.

Mikesell, H.E.; Lucy, E.

1998-02-03T23:59:59.000Z

83

Temporal Variability of Waves at the Proton Cyclotron Frequency Upstream from Mars: Implications for Mars Distant Hydrogen Exosphere  

E-Print Network (OSTI)

We report on the temporal variability of the occurrence of waves at the local proton cyclotron frequency upstream from the Martian bow shock from Mars Global Surveyor observations during the first aerobraking and science phasing orbit periods. Observations at high southern latitudes during minimum-to-mean solar activity show that the wave occurrence rate is significantly higher around perihelion southern summer solstice and lower around the same hemisphere's spring and autumn equinoxes. A similar trend is observed in the hydrogen (H) exospheric density profiles over the Martian South Pole obtained from a model including UV thermospheric heating effects. In spite of the complexity in the ion pick-up and plasma wave generation and evolution processes, these results support the idea that variations in the occurrence of waves could be used to study the temporal evolution of the distant Martian H corona and its coupling with the thermosphere at altitudes currently inaccessible to direct measurements.

Bertucci, Cesar; Chaufray, Jean-Yves; Gomez, Daniel; Mazelle, Christian; Delva, Magda; Modolo, Ronan; Gonzalez-Galindo, Francisco; Brain, David Andrew

2013-01-01T23:59:59.000Z

84

Measurable energy savings of installing variable frequency drives for cooling towers’ fans, compared to dual speed motors  

Science Journals Connector (OSTI)

Abstract In recent years the building management system (BMS) controllers have been used to control the operation of heating, ventilation, and air conditioning system in addition to lighting and some electrical equipment in order to save energy. In the water cooled system, the BMS controls the operation process of the cooling towers (CTs) fans of dual speed motors to maintain a constant leaving water temperature for different cooling loads and different ambient wet bulb temperature (WBT). This paper presents the effect of installing variable frequency drives (VFDs) for \\{CTs\\} fans in Kuwait during summer season on energy savings compared to dual speed control. The results have shown that with VFD mode, the reduction in water consumption was over 13% compared to the commonly used dual speed mode. More importantly, the combined power for the chillers and the \\{CTs\\} fans for the same amount of cooling produced were reduced by 5.8% in the VFD mode.

E. Al-Bassam; R. Alasseri

2013-01-01T23:59:59.000Z

85

Low-frequency variability and heat transport in a low-order nonlinear coupled ocean-atmosphere model  

E-Print Network (OSTI)

We formulate and study a low-order nonlinear coupled ocean-atmosphere model with an emphasis on the impact of radiative and heat fluxes and of the frictional coupling between the two components. This model version extends a previous 24-variable version by adding a dynamical equation for the passive advection of temperature in the ocean, together with an energy balance model. The bifurcation analysis and the numerical integration of the model reveal the presence of low-frequency variability (LFV) concentrated on and near a long-periodic, attracting orbit. This orbit combines atmospheric and oceanic modes, and it arises for large values of the meridional gradient of radiative input and of frictional coupling. Chaotic behavior develops around this orbit as it loses its stability; this behavior is still dominated by the LFV on decadal and multi-decadal time scales that is typical of oceanic processes. Atmospheric diagnostics also reveals the presence of predominant low- and high-pressure zones, as well as of a subtropical jet; these features recall realistic climatological properties of the oceanic atmosphere. Finally, a predictability analysis is performed. Once the decadal-scale periodic orbits develop, the coupled system's short-term instabilities --- as measured by its Lyapunov exponents --- are drastically reduced, indicating the ocean's stabilizing role on the atmospheric dynamics. On decadal time scales, the recurrence of the solution in a certain region of the invariant subspace associated with slow modes displays some extended predictability, as reflected by the oscillatory behavior of the error for the atmospheric variables at long lead times.

Stéphane Vannitsem; Jonathan Demaeyer; Lesley De Cruz; Michael Ghil

2014-12-01T23:59:59.000Z

86

Use of Frequency Response Metrics to Assess the Planning and Operating Requirements for Reliable Integration of Variable Renewable Generation  

E-Print Network (OSTI)

and energy storage. Use of Frequency Response Metrics toand energy storage. xxix Use of Frequency Response Metricsfrequency control such as demand response and energy storage.

Eto, Joseph H.

2011-01-01T23:59:59.000Z

87

Abstract--The induction motor is well known as the workhorse of industry. The development of variable speed  

E-Print Network (OSTI)

of variable speed induction motor drives has a long history of more than four decades. Today's sophisticated--Induction motor control I. INTRODUCTION EFORE the invention of variable frequency voltage and current source inverters the induction motor was never thought as continuously variable speed drive. Only some adaptations

Paderborn, Universität

88

A techno-economic analysis of cost savings for retrofitting industrial aerial coolers with variable frequency drives  

Science Journals Connector (OSTI)

A techno-economic model was created in order to develop curves that show the typical annual energy savings, rate of return, and payback for retrofitting aerial coolers with variable frequency drives (VFDs) for up to 50 motors, motor sizes from 4 to 186 kW (5–250 hp), and varying climate conditions. The cost savings due to installing a VFD depends on the reduction in energy used, as well as the reduction in power demand, the capital cost of the VFD, installation cost of the VFD, change in operating cost, and cost of electricity. The geographic locations examined in this report were Fort McMurray, Calgary, Vancouver, and Thunder Bay. This study found that the IRR increases rapidly with motor size, becomes greater than 10% at a motor size of approximately 15 kW, and may be as high as 220% (for the case of fifty, 186 kW motors). The IRR is sensitive to the number of fan motors retrofitted with VFDs, however the sensitivity rapidly declines as the number of motors is increased beyond five. The simple payback period becomes less than 1 year and nearly independent of number of motors and motor size for motors larger than 90 kW. Ambient temperature and geographic location affect the profitability of the investment, although the IRR only changes by approximately 4%.

Patrick Miller; Babatunde Olateju; Amit Kumar

2012-01-01T23:59:59.000Z

89

Voltage controlled stand-alone microhydro induction generator system  

Science Journals Connector (OSTI)

The paper discusses simulated control cases of the wound rotor self-excited induction generator WRSEIG. The generator external controller is designed to regulate the output voltage and frequency for constant or variable speed operation of the prime mover and has the inherent capability of protecting the load from short circuit, which permits voltage collapse under heavy loads. WRSEIG is self-excited using one set of excitation capacitance connected across the generator stator side. At the rotor side, a PWM controlled resistor is connected to the rotor windings through the rotating slips and act as a slip power controller. The controller can be configured to regulate the voltage as the speed or the load changes. The presented system has the capability to generate good quality AC power source with minimum controlling elements and can operate under constant or adjustable prime mover speed that suits many microhydro electricity-generating plants.

K.A. Nigim

2005-01-01T23:59:59.000Z

90

Analysis of the Effects of Severe Voltage Unbalance on the DC Bus of a Variable Frequency Drive and DC Bus Passive Filtering Harmonic Mitigation.  

E-Print Network (OSTI)

?? The power quality of a distribution system can greatly effect the way devices connected to that power source operate. Sometimes one poor power quality… (more)

Fawole, Olusola

2013-01-01T23:59:59.000Z

91

LM2907LM2917FrequencytoVoltageConverter February 1995  

E-Print Network (OSTI)

TL H 7942 LM2907LM2917FrequencytoVoltageConverter February 1995 LM2907 LM2917 Frequency to Voltage Converter General Description The LM2907 LM2917 series are monolithic frequency to voltage converters doubling for low ripple full input protection in two versions (LM2907-8 LM2917-8) and its output swings

Wedeward, Kevin

92

Entangling the optical frequency comb: simultaneous generation of multiple 2x2 and 2x3 continuous-variable cluster states in a single optical parametric oscillator  

E-Print Network (OSTI)

We report on our research effort to generate large-scale multipartite optical-mode entanglement using as few physical resources as possible. We have previously shown that cluster- and GHZ-type N-partite continuous-variable entanglement can be obtained in an optical resonator that contains a suitably designed second-order nonlinear optical medium, pumped by at most O(N^2) fields. In this paper, we show that the frequency comb of such a resonator can be entangled into an arbitrary number of independent 2x2 and 2x3 continuous-variable cluster states by a single optical parametric oscillator pumped by just a few optical modes.

Hussain Zaidi; Nicolas C. Menicucci; Steven T. Flammia; Russell Bloomer; Matthew Pysher; Olivier Pfister

2010-10-25T23:59:59.000Z

93

Analysis on the energy efficiency of variable-frequency air conditioners (Hitachi models as an example) Jim Jr-Min Lin 2014.09.26  

E-Print Network (OSTI)

Analysis on the energy efficiency of variable-frequency air conditioners (Hitachi models (Max) Energy Efficiency @min load Energy Efficiency @Max load kW kW kW kW W/W W/W RAS-22NB 1.00 3.20 0 Efficiency @min load Energy Efficiency @Max load kW kW kW kW W/W W/W RAM-5FNS(B) - 12.5 - 2.91 - 4.3 RAM-6FNS

94

Voltage stabilization system in traction substation of urban electric transport  

Science Journals Connector (OSTI)

The direct current-voltage stabilization system using a high-frequency link in traction substations of urban electric transport based on applying...

S. V. Shapiro; S. F. Muftiev

2011-02-01T23:59:59.000Z

95

Ignition distributor voltage generator  

SciTech Connect

This patent describes a voltage pulse generator and ignition distributor comprising, a base, a shaft rotatably supported by the base, a distributor cap supported by the base having a center electrode and circumferentially spaced outer electrodes. The pulse generator and ignition distribution also include a first rotor driven by the shaft formed of electrical insulating material having electrically conductive means connected to the center terminal and a portion that rotates past the outer electrodes. The portion of the electrically conductive means that rotates past the outer electrodes is spaced from the outer electrodes to form a gap therebetween. A voltage pulse generator comprises a second rotor driven by the shaft, at least one permanent magnet and an annular pickup coil supported by the base. The pickup coil has inner turns and outer turns, the beginning turn of the inner turns connected to a first lead and the last turn of the outer turns connected to a second lead, the outer turns enclosing the inner turns. The pickup coil also has a circuit connected directly between the second lead and ground which is operative to provide a direct conductive path to ground for high frequency energy capacitively coupled to the outer turns from the gap discharge between the electrically conductive means of the first rotor and an outer electrode, the outer turns forming a grounded shield for the inner turns.

Boyer, J.A.

1986-11-04T23:59:59.000Z

96

Theoretical model for evaluation of variable frequency drive for cooling water pumps in sea water based once through condenser cooling water systems  

Science Journals Connector (OSTI)

In sea water based once through cooling water system for power plants, sea water is pumped through the condenser and the return hot water is let back to sea. The cooling water pumps (CWP) in power plants generally operate at constant speed, pumping variable quantities of water depending on the tide level in the sea. The variable flow causes variation in condenser back pressure resulting in changes in the turbine cycle heat rate. If the pump speed is controlled using a variable frequency drive (VFD) to maintain design flow irrespective of the tide level, the CWP power consumption can be reduced compared to the case with constant speed CWP. However, the turbine cycle heat rate benefit that could have accrued at tide levels above the pre defined level (for fixing the CWP head) with constant speed CWP would have to be sacrificed. This paper provides a theoretical model with a typical case study to establish viability of providing VFD for \\{CWPs\\} in power plants with sea water based once through condenser cooling water system.

R. Harish; E.E. Subhramanyan; R. Madhavan; S. Vidyanand

2010-01-01T23:59:59.000Z

97

Wind Power Plant Voltage Stability Evaluation: Preprint  

SciTech Connect

Voltage stability refers to the ability of a power system to maintain steady voltages at all buses in the system after being subjected to a disturbance from a given initial operating condition. Voltage stability depends on a power system's ability to maintain and/or restore equilibrium between load demand and supply. Instability that may result occurs in the form of a progressive fall or rise of voltages of some buses. Possible outcomes of voltage instability are the loss of load in an area or tripped transmission lines and other elements by their protective systems, which may lead to cascading outages. The loss of synchronism of some generators may result from these outages or from operating conditions that violate a synchronous generator's field current limit, or in the case of variable speed wind turbine generator, the current limits of power switches. This paper investigates the impact of wind power plants on power system voltage stability by using synchrophasor measurements.

Muljadi, E.; Zhang, Y. C.

2014-09-01T23:59:59.000Z

98

Quantum theory of optical temporal phase and instantaneous frequency. II. Continuous-time limit and state-variable approach to phase-locked loop design  

SciTech Connect

We consider the continuous-time version of our recently proposed quantum theory of optical temporal phase and instantaneous frequency [M. Tsang et al., Phys. Rev. A 78, 053820 (2008)]. Using a state-variable approach to estimation, we design homodyne phase-locked loops that can measure the temporal phase with quantum-limited accuracy. We show that postprocessing can further improve the estimation performance if delay is allowed in the estimation. We also investigate the fundamental uncertainties in the simultaneous estimation of harmonic-oscillator position and momentum via continuous optical phase measurements from the classical estimation theory perspective. In the case of delayed estimation, we find that the inferred uncertainty product can drop below that allowed by the Heisenberg uncertainty relation. Although this result seems counterintuitive, we argue that it does not violate any basic principle of quantum mechanics.

Tsang, Mankei; Shapiro, Jeffrey H. [Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Lloyd, Seth [Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)

2009-05-15T23:59:59.000Z

99

Substation voltage upgrading  

SciTech Connect

This report addresses specific issues to support sound yet not unduly conservative uprating practices for substations. The main parts of the report cover the insulation withstand and overvoltage protection aspects, environmental measurements, reliability criteria, and industry experience. First the insulation design concerns are addressed. Substation stress by a backflashover of the line insulation due to lightning in the vicinity of the substation is recognized as a critical stress. A representative part of a 550 kV BIL substation was erected at the EPRI High Voltage Transmission Research Center, where also a special test circuit was assembled to produce a fast front, slow tail (0.2/200 {mu}s) wave. The substation as well as some special configurations were tested for line-to-ground and line-to-line withstand. Computer studies were performed to complement the test results. A number of important conclusions was reached. The most prominent result in that the high frequency oscillations, as caused by reflections within the substation, do not effect the Critical Flashover Voltage (CFO). The present practice, based on the highest peak is therefore very conservative. The slow tail of the wave appears to dictate the CFO. An arrester model for computer studies to represent very fast as well as slow phenomena was derived. It is based on full scale arrester test data, made available in this project. The computer program to calculate arrester model parameters is also a part of the report. The electric environmental measurements are reported for the tested substation at the HVTRC and for the uprated substation of Public Service Company of Colorado, both before and after the uprating. The performance is satisfactory when corona free hardware is used. Insulation design criteria are analyzed based on substation reliability, the system viewpoint and consequences of the failure. Utility experience with uprated substations is reviewed.

Panek, J.; Elahi, H.; Lux, A.; Imece, A.F. (General Electric Co., Schenectady, NY (United States). Power Systems Engineering Dept.); LaPanse, R.A.; Stewart, J.R. (Public Service Co. of Colorado, Denver, CO (United States))

1992-04-01T23:59:59.000Z

100

Automatic voltage imbalance detector  

DOE Patents (OSTI)

A device for indicating and preventing damage to voltage cells such as galvanic cells and fuel cells connected in series by detecting sequential voltages and comparing these voltages to adjacent voltage cells. The device is implemented by using operational amplifiers and switching circuitry is provided by transistors. The device can be utilized in battery powered electric vehicles to prevent galvanic cell damage and also in series connected fuel cells to prevent fuel cell damage.

Bobbett, Ronald E. (Los Alamos, NM); McCormick, J. Byron (Los Alamos, NM); Kerwin, William J. (Tucson, AZ)

1984-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "frequency variable voltage" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


101

Analysis of variable-frequency currents superimposed on DC currents in asynchronous HVDC Links in stressing turbine-generator-exciter shafts  

SciTech Connect

Ripple currents on the DC side of both HVDC asynchronous and synchronous Links can excite in some circumstances onerous torsional vibrations in large steam generator shafts. The problem has assumed importance in recent months on account of the HVDC Link between Scotland and Northern Ireland going ahead, on account of the proposed Eire/Wales Link, because AC/DC/AC couplers are to be installed to interconnect the East and West European Grid Systems, and because resonances have been observed on machines in close proximity to AC/DCIAC couplers and HVDC Links. This paper discusses and analyses excitation of shaft torsional vibrations in steam turbine-generator-exciter shafts in close proximity to HVDC converter stations by variable-frequency ripple currents superimposed on DC currents in asynchronous Links. It presents technical knowledge not arranged for convenient reference heretofore in studying possible excitation of turbine-generator-v/ exciter shaft torsional vibrations by non-characteristic HVDC converter harmonic currents if a machine should be considered to be at risk. Shaft torques in multi-machine networks are evaluated by proportioning HVDC Link disturbance currents to each machine at risk using system network data, generator data and fault analysis data considering frequency dependence of the system parameters. This scaling factor is calculated for different scenarios of system operation and load. Equivalent circuits for the synchronous generator are employed appropriately to correlate HVDC Link disturbance current impressed on the generator stator with s state torque excitation from which magnitude of turbine-generator-exciter shaft torque is deduced.

Hammons, T.J.; Bremner, J.J. [Univ. of Glasgow (United Kingdom)] [Univ. of Glasgow (United Kingdom)

1995-03-01T23:59:59.000Z

102

High voltage RF feedthrough bushing  

DOE Patents (OSTI)

Described is a multi-element, high voltage radio frequency bushing for trmitting RF energy to an antenna located in a vacuum container. The bushing includes a center conductor of complex geometrical shape, an outer coaxial shield conductor, and a thin-walled hollow truncated cone insulator disposed between central and outer conductors. The shape of the center conductor, which includes a reverse curvature portion formed of a radially inwardly directed shoulder and a convex portion, controls the uniformity of the axial surface gradient on the insulator cone. The outer shield has a first substantially cylindrical portion and a second radially inwardly extending truncated cone portion.

Grotz, Glenn F. (Huntington Station, NY)

1984-01-01T23:59:59.000Z

103

Strategies for Low Carbon Growth In India: Industry and Non Residential Sectors  

E-Print Network (OSTI)

Variable Voltage Variable Frequency drives to control oxygeninstallation of variable frequency drives; installation ofrecovery system Variable frequency drives Lighting Fiber

Sathaye, Jayant

2011-01-01T23:59:59.000Z

104

A new technique to reject dc-link voltage ripple in PWM inverters  

E-Print Network (OSTI)

on the rlc-link, is numerically calculated. Let us assume, Inverfer output frequency f, ? 60 Hz Vs, = 1 pu Dc ? link voltage rrpple = k Vs, ? 0. 2 x Vge = . 2 pu Dc ? link voltage ripple frequency f, = 120 Hz :tfodulation index ? 0. 5 Frequency spectrum...

Shireen, Wajiha

1990-01-01T23:59:59.000Z

105

Constant voltage ultracapacitor  

Science Journals Connector (OSTI)

Ultracapacitors have attracted lots of attention recently due to their growing use in hybrid vehicles and in energy storage applications for the smart grid. A very undesirable feature of ultracapacitors is the fact that the voltage drops as the capacitor is discharged. DC-DC converters are employed at present to convert the voltage of the ultracapacitor to constant voltage; however these converters typically do not operate if the voltage of the ultracapacitor drops below 1?V. In addition DC-DC converters suffer from well-known size/efficiency tradeoffs. This paper introduces a novel new ultracapacitor that is characterized by constant voltage. The new ultracapacitor does not utilize familiar energy conversion principles. Rather operation depends on an embedded electromechanical system that actually alters the capacitance of the ultracapacitor as the device is discharged. Due to a simple proportionality relationship between charge capacitance and voltage the voltage remains constant. Theoretical and experimental investigations have shown that the embedded mechanism for altering the capacitance has an efficiency of 99% or higher.

Ezzat G. Bakhoum

2012-01-01T23:59:59.000Z

106

Voltage balanced multilevel voltage source converter system  

DOE Patents (OSTI)

A voltage balanced multilevel converter for high power AC applications such as adjustable speed motor drives and back-to-back DC intertie of adjacent power systems. This converter provides a multilevel rectifier, a multilevel inverter, and a DC link between the rectifier and the inverter allowing voltage balancing between each of the voltage levels within the multilevel converter. The rectifier is equipped with at least one phase leg and a source input node for each of the phases. The rectifier is further equipped with a plurality of rectifier DC output nodes. The inverter is equipped with at least one phase leg and a load output node for each of the phases. The inverter is further equipped with a plurality of inverter DC input nodes. The DC link is equipped with a plurality of rectifier charging means and a plurality of inverter discharging means. The plurality of rectifier charging means are connected in series with one of the rectifier charging means disposed between and connected in an operable relationship with each adjacent pair of rectifier DC output nodes. The plurality of inverter discharging means are connected in series with one of the inverter discharging means disposed between and connected in an operable relationship with each adjacent pair of inverter DC input nodes. Each of said rectifier DC output nodes are individually electrically connected to the respective inverter DC input nodes. By this means, each of the rectifier DC output nodes and each of the inverter DC input nodes are voltage balanced by the respective charging and discharging of the rectifier charging means and the inverter discharging means.

Peng, Fang Zheng (Oak Ridge, TN); Lai, Jih-Sheng (Knoxville, TN)

1997-01-01T23:59:59.000Z

107

Voltage balanced multilevel voltage source converter system  

DOE Patents (OSTI)

Disclosed is a voltage balanced multilevel converter for high power AC applications such as adjustable speed motor drives and back-to-back DC intertie of adjacent power systems. This converter provides a multilevel rectifier, a multilevel inverter, and a DC link between the rectifier and the inverter allowing voltage balancing between each of the voltage levels within the multilevel converter. The rectifier is equipped with at least one phase leg and a source input node for each of the phases. The rectifier is further equipped with a plurality of rectifier DC output nodes. The inverter is equipped with at least one phase leg and a load output node for each of the phases. The inverter is further equipped with a plurality of inverter DC input nodes. The DC link is equipped with a plurality of rectifier charging means and a plurality of inverter discharging means. The plurality of rectifier charging means are connected in series with one of the rectifier charging means disposed between and connected in an operable relationship with each adjacent pair of rectifier DC output nodes. The plurality of inverter discharging means are connected in series with one of the inverter discharging means disposed between and connected in an operable relationship with each adjacent pair of inverter DC input nodes. Each of said rectifier DC output nodes are individually electrically connected to the respective inverter DC input nodes. By this means, each of the rectifier DC output nodes and each of the inverter DC input nodes are voltage balanced by the respective charging and discharging of the rectifier charging means and the inverter discharging means. 15 figs.

Peng, F.Z.; Lai, J.S.

1997-07-01T23:59:59.000Z

108

Substation voltage upgrading  

SciTech Connect

Substation voltage uprating, i.e., conversion of a substation from a lower rated voltage to a higher rated voltage without a complete substation rebuild, can lead to excellent economic benefits. Utilization of the old substation layout and/or the existing equipment, to some extent, is the practical objective of such an uprating. The objective of this project was to assess the opportunities for substation uprating in the industry, to establish feasibility for such uprating and to study methods for accomplishing it. The final aim of the project was to provide guidance to utilities interested in uprating. 56 refs., 41 figs., 18 tabs.

Panek, J.; Elahi, H.; Sublich, M. (General Electric Co., Schenectady, NY (USA). Systems Development and Engineering Dept.)

1989-08-01T23:59:59.000Z

109

High voltage DC power supply  

DOE Patents (OSTI)

A high voltage DC power supply having a first series resistor at the output for limiting current in the event of a short-circuited output, a second series resistor for sensing the magnitude of output current, and a voltage divider circuit for providing a source of feedback voltage for use in voltage regulation is disclosed. The voltage divider circuit is coupled to the second series resistor so as to compensate the feedback voltage for a voltage drop across the first series resistor. The power supply also includes a pulse-width modulated control circuit, having dual clock signals, which is responsive to both the feedback voltage and a command voltage, and also includes voltage and current measuring circuits responsive to the feedback voltage and the voltage developed across the second series resistor respectively. 7 figs.

Droege, T.F.

1989-12-19T23:59:59.000Z

110

High voltage DC power supply  

DOE Patents (OSTI)

A high voltage DC power supply having a first series resistor at the output for limiting current in the event of a short-circuited output, a second series resistor for sensing the magnitude of output current, and a voltage divider circuit for providing a source of feedback voltage for use in voltage regulation is disclosed. The voltage divider circuit is coupled to the second series resistor so as to compensate the feedback voltage for a voltage drop across the first series resistor. The power supply also includes a pulse-width modulated control circuit, having dual clock signals, which is responsive to both the feedback voltage and a command voltage, and also includes voltage and current measuring circuits responsive to the feedback voltage and the voltage developed across the second series resistor respectively.

Droege, Thomas F. (Batavia, IL)

1989-01-01T23:59:59.000Z

111

Low-voltage gyrotrons  

SciTech Connect

For a long time, the gyrotrons were primarily developed for electron cyclotron heating and current drive of plasmas in controlled fusion reactors where a multi-megawatt, quasi-continuous millimeter-wave power is required. In addition to this important application, there are other applications (and their number increases with time) which do not require a very high power level, but such issues as the ability to operate at low voltages and have compact devices are very important. For example, gyrotrons are of interest for a dynamic nuclear polarization, which improves the sensitivity of the nuclear magnetic resonance spectroscopy. In this paper, some issues important for operation of gyrotrons driven by low-voltage electron beams are analyzed. An emphasis is made on the efficiency of low-voltage gyrotron operation at the fundamental and higher cyclotron harmonics. These efficiencies calculated with the account for ohmic losses were, first, determined in the framework of the generalized gyrotron theory based on the cold-cavity approximation. Then, more accurate, self-consistent calculations for the fundamental and second harmonic low-voltage sub-THz gyrotron designs were carried out. Results of these calculations are presented and discussed. It is shown that operation of the fundamental and second harmonic gyrotrons with noticeable efficiencies is possible even at voltages as low as 5-10 kV. Even the third harmonic gyrotrons can operate at voltages about 15 kV, albeit with rather low efficiency (1%-2% in the submillimeter wavelength region).

Glyavin, M. Yu.; Zavolskiy, N. A.; Sedov, A. S. [Institute of Applied Physics RAS, N. Novgorod 603600 (Russian Federation); Nusinovich, G. S. [IREAP, University of Maryland, College Park, Maryland 20742-3511 (United States)

2013-03-15T23:59:59.000Z

112

Design and applications of a flicker voltage generator  

SciTech Connect

In this paper, a 200W flicker voltage generator is made by using microcomputers and linear amplification circuits. The modulation amplitudes and frequencies based on the UIE {Delta}V{sub 10} evaluation can be arbitrarily assigned by software with high accuracy. The flicker voltage signals measured at the customer side also can be re-generated. Some applications, such as evaluating the effects of flicker voltage on incandescent and compact fluorescent lamps (CFLs), are also made. From experimental tests by use of the flicker voltage generator, the properties of some compact fluorescent lamps and incandescent lamps are compared. Those properties describe the relation between input voltage variation and output flux of lamps, such that there is direct description of influences of flicker voltages on lamps.

Chang, W.N.; Wu, C.J. [National Taiwan Inst. of Tech., Peitow-Taipei (Taiwan, Province of China). Dept. of Electrical Engineering

1995-12-31T23:59:59.000Z

113

Voltage controlled current source  

DOE Patents (OSTI)

A seven decade, voltage controlled current source is described for use in testing intermediate range nuclear instruments that covers the entire test current range of from 10 picoamperes to 100 microamperes. High accuracy is obtained throughout the entire seven decades of output current with circuitry that includes a coordinated switching scheme responsive to the input signal from a hybrid computer to control the input voltage to an antilog amplifier, and to selectively connect a resistance to the antilog amplifier output to provide a continuous output current source as a function of a preset range of input voltage. An operator controlled switch provides current adjustment for operation in either a real-time simulation test mode or a time response test mode.

Casne, Gregory M. (Pittsburgh, PA)

1992-01-01T23:59:59.000Z

114

High-voltage engineering  

E-Print Network (OSTI)

High-voltage engineering covers the application, the useful use and proper working of high voltages and high fields. Here we give some introductory examples, i.e., ‘septa’ and ‘kicker’ at the Large Hadron Collider (14 TeV), the Super Proton Synchrotron (450 GeV) and the Proton Synchrotron (26 GeV) accelerators as found at the European Orginization for Nuclear Research (CERN) today. We briefly cover the theoretical foundation (Maxwell equations) and aspects of numerical field simulation methods. Concepts relating to electrical fields, insulation geometry and medium and breakdown are introduced. We discuss ways of generating high voltages with examples of AC sources (50/60 Hz), DC sources, and pulse sources. Insulation and breakdown in gases, liquids, solids and vacuum are presented, including Paschen’s law (breakdown field and streamer breakdown). Applications of the above are discussed, in particular the general application of a transformer. We briefly discuss measurement techniques of partial disch...

Gaxiola, E

2006-01-01T23:59:59.000Z

115

High voltage pulse conditioning  

DOE Patents (OSTI)

Apparatus for conditioning high voltage pulses from particle accelerators in order to shorten the rise times of the pulses. Flashover switches in the cathode stalk of the transmission line hold off conduction for a determinable period of time, reflecting the early portion of the pulses. Diodes upstream of the switches divert energy into the magnetic and electrostatic storage of the capacitance and inductance inherent to the transmission line until the switches close.

Springfield, Ray M. (Sante Fe, NM); Wheat, Jr., Robert M. (Los Alamos, NM)

1990-01-01T23:59:59.000Z

116

E-beam high voltage switching power supply  

DOE Patents (OSTI)

A high-power power supply produces a controllable, constant high voltage put under varying and arcing loads. The power supply includes a voltage regulator, an inductor, an inverter for producing a high frequency square wave current of alternating polarity, an improved inverter voltage clamping circuit, a step up transformer, an output rectifier for producing a dc voltage at the output of each module, and a current sensor for sensing output current. The power supply also provides dynamic response to varying loads by controlling the voltage regulator duty cycle and circuitry is provided for sensing incipient arc currents at the output of the power supply to simultaneously decouple the power supply circuitry from the arcing load. The power supply includes a plurality of discrete switching type dc--dc converter modules.

Shimer, Daniel W. (Danville, CA); Lange, Arnold C. (Livermore, CA)

1996-01-01T23:59:59.000Z

117

E-beam high voltage switching power supply  

DOE Patents (OSTI)

A high-power power supply produces a controllable, constant high voltage output under varying and arcing loads. The power supply includes a voltage regulator, an inductor, an inverter for producing a high frequency square wave current of alternating polarity, an improved inverter voltage clamping circuit, a step up transformer, an output rectifier for producing a dc voltage at the output of each module, and a current sensor for sensing output current. The power supply also provides dynamic response to varying loads by controlling the voltage regulator duty cycle and circuitry is provided for sensing incipient arc currents at the output of the power supply to simultaneously decouple the power supply circuitry from the arcing load. The power supply includes a plurality of discrete switching type dc--dc converter modules. 5 figs.

Shimer, D.W.; Lange, A.C.

1996-10-15T23:59:59.000Z

118

Charge-pump voltage converter  

DOE Patents (OSTI)

A charge-pump voltage converter for converting a low voltage provided by a low-voltage source to a higher voltage. Charge is inductively generated on a transfer rotor electrode during its transit past an inductor stator electrode and subsequently transferred by the rotating rotor to a collector stator electrode for storage or use. Repetition of the charge transfer process leads to a build-up of voltage on a charge-receiving device. Connection of multiple charge-pump voltage converters in series can generate higher voltages, and connection of multiple charge-pump voltage converters in parallel can generate higher currents. Microelectromechanical (MEMS) embodiments of this invention provide a small and compact high-voltage (several hundred V) voltage source starting with a few-V initial voltage source. The microscale size of many embodiments of this invention make it ideally suited for MEMS- and other micro-applications where integration of the voltage or charge source in a small package is highly desirable.

Brainard, John P. (Albuquerque, NM); Christenson, Todd R. (Albuquerque, NM)

2009-11-03T23:59:59.000Z

119

High voltage dc--dc converter with dynamic voltage regulation and decoupling during load-generated arcs  

DOE Patents (OSTI)

A high-power power supply produces a controllable, constant high voltage output under varying and arcing loads. The power supply includes a voltage regulator, an inductor, an inverter for producing a high frequency square wave current of alternating polarity, an improved inverter voltage clamping circuit, a step up transformer, an output rectifier for producing a dc voltage at the output of each module, and a current sensor for sensing output current. The power supply also provides dynamic response to varying loads by controlling the voltage regulator duty cycle and circuitry is provided for sensing incipient arc currents at the output of the power supply to simultaneously decouple the power supply circuitry from the arcing load. The power supply includes a plurality of discrete switching type dc--dc converter modules. 5 Figs.

Shimer, D.W.; Lange, A.C.

1995-05-23T23:59:59.000Z

120

High voltage dc-dc converter with dynamic voltage regulation and decoupling during load-generated arcs  

DOE Patents (OSTI)

A high-power power supply produces a controllable, constant high voltage output under varying and arcing loads. The power supply includes a voltage regulator, an inductor, an inverter for producing a high frequency square wave current of alternating polarity, an improved inverter voltage clamping circuit, a step up transformer, an output rectifier for producing a dc voltage at the output of each module, and a current sensor for sensing output current. The power supply also provides dynamic response to varying loads by controlling the voltage regulator duty cycle and circuitry is provided for sensing incipient arc currents at the output of the power supply to simultaneously decouple the power supply circuitry from the arcing load. The power supply includes a plurality of discrete switching type dc--dc converter modules.

Shimer, Daniel W. (Danville, CA); Lange, Arnold C. (Livermore, CA)

1995-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "frequency variable voltage" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


121

Current-based direct power control of a DFIG under unbalanced grid voltage  

Science Journals Connector (OSTI)

Abstract A novel current-based direct power control (CB-DPC) strategy for a grid-connected doubly-fed induction generator (DFIG) is proposed. The reported control scheme is applicable to DFIG-based variable-speed wind turbines that operate under unbalanced network voltages. The required DFIG rotor voltage for precise regulation of the stator active and reactive output powers and accurate elimination of their inherent pulsations are directly obtained using a nonlinear integral sliding-mode control (ISMC) scheme. Compared with other control methods, the proposed strategy is simpler since it is not based on the symmetrical components theory, does not need multiple synchronous coordinate transformations, and only requires DFIG voltage and current values as its inputs. Constant switching frequency of the rotor-side converter (RSC) is achieved by means of space vector pulse-width modulation (SVPWM) technique. Uncertainties in the parameters of the generator are included in the design. A compensation strategy is also proposed for tracking error mitigation of the powers that occur due to elimination of the chattering phenomena in the ISMC scheme. Simulation results on a 2MW DFIG under different operating conditions are presented to validate the effectiveness and robustness of the proposed method.

Mohammad Farshadnia; Seyed Abbas Taher

2014-01-01T23:59:59.000Z

122

Hybrid permanent magnet and variable reluctance generator  

SciTech Connect

This patent describes a hybrid electrical generator. It comprises: a permanent magnet generator having a permanent magnet rotor mounted on a shaft, the permanent magnet generator providing an output voltage over an operating range which falls in response to an increasing electrical load; a variable reluctance generator having a rotor mounted on the shaft with excitation of a stator of the variable reluctance generator being provided from the permanent magnet generator, the variable reluctance generator providing an output voltage which varies in response to an increasing electrical load over an operating range; and a voltage regulator, responsive to combined output voltages of the generators, for controlling the output voltage provided by the variable reluctance generator.

Vaidya, J.; Belanger, D.J.

1990-09-25T23:59:59.000Z

123

Oscillator Architectures and Enhanced Frequency Synthesizer  

E-Print Network (OSTI)

A voltage controlled oscillator (VCO), that generates a periodic signal whose frequency is tuned by a voltage, is a key building block in any integrated circuit systems. A sine wave oscillator can be used for a built-in self testing where high...

Park, Sang Wook

2009-11-16T23:59:59.000Z

124

Electro-optic high voltage sensor  

DOE Patents (OSTI)

A small sized electro-optic voltage sensor capable of accurate measurement of high levels of voltages without contact with a conductor or voltage source is provided. When placed in the presence of an electric field, the sensor receives an input beam of electromagnetic radiation into the sensor. A polarization beam displacer serves as a filter to separate the input beam into two beams with orthogonal linear polarizations. The beam displacer is oriented in such a way as to rotate the linearly polarized beams such that they enter a Pockels crystal having at a preferred angle of 45 degrees. The beam displacer is therefore capable of causing a linearly polarized beam to impinge a crystal at a desired angle independent of temperature. The Pockels electro-optic effect induces a differential phase shift on the major and minor axes of the input beam as it travels through the Pockels crystal, which causes the input beam to be elliptically polarized. A reflecting prism redirects the beam back through the crystal and the beam displacer. On the return path, the polarization beam displacer separates the elliptically polarized beam into two output beams of orthogonal linear polarization representing the major and minor axes. The system may include a detector for converting the output beams into electrical signals, and a signal processor for determining the voltage based on an analysis of the output beams. The output beams are amplitude modulated by the frequency of the electric field and the amplitude of the output beams is proportional to the magnitude of the electric field, which is related to the voltage being measured.

Davidson, James R. (Idaho Falls, ID); Seifert, Gary D. (Idaho Falls, ID)

2002-01-01T23:59:59.000Z

125

Planning of distribution networks for medium voltage and low voltage.  

E-Print Network (OSTI)

??Determination of the placement and rating of transformers and feeders are the main objective of the basic distribution network planning. The bus voltage and the… (more)

Ziari, Iman

2011-01-01T23:59:59.000Z

126

Voltage Regulator Chip: Power Supplies on a Chip  

SciTech Connect

ADEPT Project: CPES at Virginia Tech is finding ways to save real estate on a computer's motherboard that could be used for other critical functions. Every computer processor today contains a voltage regulator that automatically maintains a constant level of electricity entering the device. These regulators contain bulky components and take up about 30% of a computer's motherboard. CPES at Virginia Tech is developing a voltage regulator that uses semiconductors made of gallium nitride on silicon (GaN-on-Si) and high-frequency soft magnetic material. These materials are integrated on a small, 3D chip that can handle the same amount of power as traditional voltage regulators at 1/10 the size and with improved efficiency. The small size also frees up to 90% of the motherboard space occupied by current voltage regulators.

None

2010-09-01T23:59:59.000Z

127

Nickel-hydrogen voltage-efficiency model  

SciTech Connect

A model for providing voltage vs. current relationships and coulombic efficiency has been developed applicable to Nickel-Hydrogen (NiH{sub 2}) batteries. The performance relationships can be used directly in dynamic electrical energy storage system models or customized by predicting the particular case of voltage as a function of applied current. The algorithm utilizes electrochemical models for competing cell reactions: a single Butler-Volmer equation for the main NiH{sub 2} reaction, and a Tafel relationship for oxygen generation. For the main NiH{sub 2} reaction, the dependence on state-of-charge is introduced via a Nerstian term containing concentrations of active materials present. Oxygen recombination and self-discharge are modeled as first order reactions. Model parameters are determined by a modified Marquardt algorithm to provide a best-fit of both voltage and pressure data to the physical model. The data fit is from electrical characterization tests which may include capacity measurements or repeated electrical cycling at specified depths-of-discharge or with particular regimens. It has been found that test performance data covering a wide domain of the independent variables (temperature, current, and state-of-charge) will produce a well-behaved model.

Hafen, D.P.; Armantrout, J.D. [Lockheed Martin Missiles and Space, Sunnyvale, CA (United States)

1996-12-31T23:59:59.000Z

128

ABBGroup-1-High voltage lab  

E-Print Network (OSTI)

;©ABBGroup-3- 3-Sep-07 Where does one use circuit breakers? High voltage (HV) circuit breakers are keyA DISTRIBUTION MEDIUM AND LOW VOLTAGE HV circuit breakers #12;©ABBGroup-4- 3-Sep-07 When a breaker fails to interrupt the current... Fault arc at a disconnector Fault arc in a substation #12;©ABBGroup-5- 3-Sep-07

Basse, Nils Plesner

129

Temperature controlled high voltage regulator  

DOE Patents (OSTI)

A temperature controlled high voltage regulator for automatically adjusting the high voltage applied to a radiation detector is described. The regulator is a solid state device that is independent of the attached radiation detector, enabling the regulator to be used by various models of radiation detectors, such as gas flow proportional radiation detectors.

Chiaro, Jr., Peter J. (Clinton, TN); Schulze, Gerald K. (Knoxville, TN)

2004-04-20T23:59:59.000Z

130

Investigation of dc precise voltage sources for use as Zener transport standard  

SciTech Connect

20 precise compact voltage sources based on zener diodes were manufactured. These sources were under investigation at measuring system in NPO VNIIFTRI during the year. A few sources with voltage drift less than 5 ppm per year and noise level lower than 100 nV in the frequency band of 0,01-10 Hz were selected for manufacturing of 4-channels dc voltage transportable reference standard. This reference standard was investigated by Russian 1-V Josephson systems.

Karpov, O.V.; Shulga, V.M.; Shakirzyanova, F.R. [National Scientifical and Research Institute for Physical Technical and Radiotechnical Measurements, Moscow (Russian Federation)

1994-12-31T23:59:59.000Z

131

A multilevel energy buffer and voltage modulator for grid-interfaced micro-inverters  

E-Print Network (OSTI)

Micro-inverters operating into the single-phase grid from solar photovoltaic (PV) panels or other low-voltage sources must buffer the twice-line-frequency variations between the energy sourced by the PV panel and that ...

Chen, Minjie

132

Low voltage nonprimary explosive detonator  

DOE Patents (OSTI)

A low voltage, electrically actuated, nonprimary explosive detonator is disclosed wherein said detonation is achieved by means of an explosive train in which a deflagration-to-detonation transition is made to occur. The explosive train is confined within a cylindrical body and positioned adjacent to low voltage ignition means have electrical leads extending outwardly from the cylindrical confining body. Application of a low voltage current to the electrical leads ignites a self-sustained deflagration in a donor portion of the explosive train which then is made to undergo a transition to detonation further down the train.

Dinegar, Robert H. (Los Alamos, NM); Kirkham, John (Newbury, GB2)

1982-01-01T23:59:59.000Z

133

E-beam high voltage switching power supply  

DOE Patents (OSTI)

A high power, solid state power supply is described for producing a controllable, constant high voltage output under varying and arcing loads suitable for powering an electron beam gun or other ion source. The present power supply is most useful for outputs in a range of about 100-400 kW or more. The power supply is comprised of a plurality of discrete switching type dc-dc converter modules, each comprising a voltage regulator, an inductor, an inverter for producing a high frequency square wave current of alternating polarity, an improved inverter voltage clamping circuit, a step up transformer, and an output rectifier for producing a dc voltage at the output of each module. The inputs to the converter modules are fed from a common dc rectifier/filter and are linked together in parallel through decoupling networks to suppress high frequency input interactions. The outputs of the converter modules are linked together in series and connected to the input of the transmission line to the load through a decoupling and line matching network. The dc-dc converter modules are phase activated such that for n modules, each module is activated equally 360{degree}/n out of phase with respect to a successive module. The phased activation of the converter modules, combined with the square current waveforms out of the step up transformers, allows the power supply to operate with greatly reduced output capacitance values which minimizes the stored energy available for discharge into an electron beam gun or the like during arcing. The present power supply also provides dynamic response to varying loads by controlling the voltage regulator duty cycle using simulated voltage feedback signals and voltage feedback loops. Circuitry is also provided for sensing incipient arc currents reflected at the output of the power supply and for simultaneously decoupling the power supply circuitry from the arcing load. 7 figs.

Shimer, D.W.; Lange, A.C.

1997-03-11T23:59:59.000Z

134

E-beam high voltage switching power supply  

DOE Patents (OSTI)

A high power, solid state power supply is described for producing a controllable, constant high voltage output under varying and arcing loads suitable for powering an electron beam gun or other ion source. The present power supply is most useful for outputs in a range of about 100-400 kW or more. The power supply is comprised of a plurality of discrete switching type dc-dc converter modules, each comprising a voltage regulator, an inductor, an inverter for producing a high frequency square wave current of alternating polarity, an improved inverter voltage clamping circuit, a step up transformer, and an output rectifier for producing a dc voltage at the output of each module. The inputs to the converter modules are fed from a common dc rectifier/filter and are linked together in parallel through decoupling networks to suppress high frequency input interactions. The outputs of the converter modules are linked together in series and connected to the input of the transmission line to the load through a decoupling and line matching network. The dc-dc converter modules are phase activated such that for n modules, each module is activated equally 360.degree./n out of phase with respect to a successive module. The phased activation of the converter modules, combined with the square current waveforms out of the step up transformers, allows the power supply to operate with greatly reduced output capacitance values which minimizes the stored energy available for discharge into an electron beam gun or the like during arcing. The present power supply also provides dynamic response to varying loads by controlling the voltage regulator duty cycle using simulated voltage feedback signals and voltage feedback loops. Circuitry is also provided for sensing incipient arc currents reflected at the output of the power supply and for simultaneously decoupling the power supply circuitry from the arcing load.

Shimer, Daniel W. (Danville, CA); Lange, Arnold C. (Livermore, CA)

1997-01-01T23:59:59.000Z

135

Definition: Automated Voltage Regulators | Open Energy Information  

Open Energy Info (EERE)

Regulators Regulators Jump to: navigation, search Dictionary.png Automated Voltage Regulators Voltage regulators are transformers that can increase or decrease the voltage on a distribution circuit to help keep the voltage within a pre-determined band. Unlike capacitor banks, voltage regulators cannot adjust power factor. These devices typically monitor the voltage at the location where they are connected, and compare it to a programmed set point. If the voltage deviates too far from the set point, the voltage regulator can increase or decrease its output voltage by moving the tap on the secondary side up or down. An automated voltage regulator can operate with remote control signals, or in concert with other area voltage control devices, to help regulate distribution voltage in a coordinated fashion.

136

High voltage electrical amplifier having a short rise time  

DOE Patents (OSTI)

A circuit, comprising an amplifier and a transformer is disclosed that produces a high power pulse having a fast response time, and that responds to a digital control signal applied through a digital-to-analog converter. The present invention is suitable for driving a component such as an electro-optic modulator with a voltage in the kilovolt range. The circuit is stable at high frequencies and during pulse transients, and its impedance matching circuit matches the load impedance with the output impedance. The preferred embodiment comprises an input stage compatible with high-speed semiconductor components for amplifying the voltage of the input control signal, a buffer for isolating the input stage from the output stage; and a plurality of current amplifiers connected to the buffer. Each current amplifier is connected to a field effect transistor (FET), which switches a high voltage power supply to a transformer which then provides an output terminal for driving a load. The transformer comprises a plurality of transmission lines connected to the FETs and the load. The transformer changes the impedance and voltage of the output. The preferred embodiment also comprises a low voltage power supply for biasing the FETs at or near an operational voltage.

Christie, David J. (Pleasanton, CA); Dallum, Gregory E. (Livermore, CA)

1991-01-01T23:59:59.000Z

137

Saving Megawatts with Voltage Optimization  

E-Print Network (OSTI)

that had been installed at several electric utility distribution substations in the U.S. and Canada. These systems, being operated in Conservation Voltage Regulation mode, have provided significant energy conservation where they have been installed...

Wilson, T.; Bell, D.

2010-01-01T23:59:59.000Z

138

Self-Excited ac High Voltage Generation Using Water Droplets  

Science Journals Connector (OSTI)

By letting water drops fall through rings into cans high voltage can be spontaneously generated with no external electrical excitation. Previous work concerning this type of electric influence machine for dc and three-phase ac high voltage generation is extended to include multiphase multifrequency operation by considering N streams and N cans. A distributed equivalent circuit representation is used to calculate the natural frequencies of the system where it is found that many overstable modes are present. Experimental observations with up to five cans are presented. This device can serve as a model for phenomena concerned with atmospheric electricity.

Markus Zahn

1973-01-01T23:59:59.000Z

139

High frequency reference electrode  

DOE Patents (OSTI)

A high frequency reference electrode for electrochemical experiments comprises a mercury-calomel or silver-silver chloride reference electrode with a layer of platinum around it and a layer of a chemically and electrically resistant material such as TEFLON around the platinum covering all but a small ring or halo' at the tip of the reference electrode, adjacent to the active portion of the reference electrode. The voltage output of the platinum layer, which serves as a redox electrode, and that of the reference electrode are coupled by a capacitor or a set of capacitors and the coupled output transmitted to a standard laboratory potentiostat. The platinum may be applied by thermal decomposition to the surface of the reference electrode. The electrode provides superior high-frequency response over conventional electrodes. 4 figs.

Kronberg, J.W.

1994-05-31T23:59:59.000Z

140

Influence of excitation frequency on plasma parameters and etching characteristics of radio-frequency discharges  

Science Journals Connector (OSTI)

Abstract Plasma parameters such as electron density, electron-collision rate, resonance frequency and the bias voltage were shown to be important for the characterization of radio-frequency (RF) plasmas. By means of self-excited electron resonance spectroscopy (SEERS), the plasma parameters were compared at two different frequencies, 13.56 \\{MHz\\} and 40.68 MHz, in argon, oxygen, fluorine and their mixtures at low pressure. Upon increasing the generator frequency, more RF power has to be applied to achieve the same bias voltage. At the lower pressure, the bias voltage indicates the mean energy of the ions impacting on the substrate and causing damage at the surface. The experimental results show that generally more power was dissipated in the plasma instead of the sheath if the frequency of the substrate generator was decreased. This results in a significantly higher electron density at the higher frequency. The increase of mean ion energy, owing to lower sheath thickness, has to be taken into account as a second-order effect. In order to show the influence of frequency for process applications, the etch rate of SiO2 on silicon was determined in CF4. For the same generator power, there is no well-pronounced dependence of the etch rate of SiO2 on silicon (CF4) on the frequency. For the same bias voltage, the etch rate of SiO2 increases roughly with the frequency.

M. Klick; L. Eichhorn; W. Rehak; M. Kammeyer; H. Mischke

1999-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "frequency variable voltage" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


141

Solutions for Interharmonics in Variable Speed Drives for LNG Plants:.  

E-Print Network (OSTI)

??Variable speed drives can cause components of any frequency known as interharmonics. Large variable speed drives in the order of tens of megawatts can replace… (more)

Verhulst, M.P.A.

2011-01-01T23:59:59.000Z

142

Dual radio frequency plasma source: Understanding via electrical asymmetry effect  

SciTech Connect

On the basis of the global model, the influences of driving voltage and frequency on electron heating in geometrically symmetrical dual capacitively coupled radio frequency plasma have been investigated. Consistent with the experimental and simulation results, non-monotonic behavior of dc self bias and plasma heating with increasing high frequency is observed. In addition to the local maxima of plasma parameters for the integer values of the ratio between the frequencies ({xi}), ourstudies also predict local maxima for odd integer values of 2{xi} as a consequence of the electrical asymmetry effect produced by dual frequency voltage sources.

Bora, B. [Departamento de Plasma Termonuclear, Comision Chilena de Energia Nuclear (CCHEN), Casilla 188-D, Santiago (Chile); Departamento de Fisica, Pontificia Universidad Catolica de Chile, Casilla 306, Santiago 22 (Chile); Bhuyan, H.; Favre, M.; Wyndham, E. [Departamento de Fisica, Pontificia Universidad Catolica de Chile, Casilla 306, Santiago 22 (Chile); Wong, C. S. [Plasma Technology Research Centre, Physics Department, Faculty of Science, University of Malaya, 50603 Kuala Lumpur (Malaysia)

2013-04-21T23:59:59.000Z

143

Voltage, energy and power in electric circuits  

E-Print Network (OSTI)

Voltage, energy and power in electric circuits Science teaching unit #12;Disclaimer The Department-2008DVD-EN Voltage, energy and power in electric circuits #12;#12;© Crown copyright 2008 1The National Strategies | Secondary Voltage, energy and power in electric circuits 00094-2008DVD-EN Contents Voltage

Berzins, M.

144

Diversity–disturbance relationships: frequency and intensity interact  

Science Journals Connector (OSTI)

...relationship depended on the frequency of disturbances by the...diversity as the response variable and frequency and intensity as factors...unequivocally that the frequency-intensity interaction drives the coexistence of ecologically...

2012-01-01T23:59:59.000Z

145

Ancillary service details: Voltage control  

SciTech Connect

Voltage control is accomplished by managing reactive power on an alternating-current power system. Reactive power can be produced and absorbed by both generation and transmission equipment. Reactive-power devices differ substantially in the magnitude and speed of response and in their capital costs. System operators, transmission owners, generators, customers, power marketers, and government regulators need to pay close attention to voltage control as they restructure the U.S. electricity industry. Voltage control can affect reliability and commerce in three ways: (1) Voltages must be maintained within an acceptable range for both customer and power-system equipment to function properly. (2) The movement of reactive power consumes transmission resources, which limits the ability to move real power and worsens congestion. (3) The movement of reactive power results in real-power losses. When generators are required to supply excessive amounts of reactive power, their real-power production must be curtailed. These opportunity costs are not currently compensated for in most regions. Current tariffs are based on embedded costs. These embedded-cost tariffs average about $0.51/MWh, equivalent to $1.5 billion annually for the United States as a whole. Although this cost is low when compared with the cost of energy, it still aggregates to a significant amount of money. This report takes a basic look at why the power system requires reactive power (an appendix explains the fundamentals of real and reactive power). The report then examines the various types of generation and transmission resources used to supply reactive power and to control voltage. Finally it discusses how these resources are deployed and paid for in several reliability regions around the country. As the U.S. electricity industry is restructured, the generation, transmission, and system-control equipment and functions that maintain voltages within the appropriate ranges are being deintegrated.

Kirby, B.; Hirst, E.

1997-12-01T23:59:59.000Z

146

Neotyphodium endophyte infection frequency in annual grass populations: relative importance of mutualism and transmission efficiency  

Science Journals Connector (OSTI)

...equilibrium infection frequency, even if infected...equilibrium infection frequency (see also Ravel...should be expected to drive the patterns of endophyte infection frequency. Variability in...environmental factors, variable proportions of viable...

2008-01-01T23:59:59.000Z

147

ABBGroup-1-High voltage lab  

E-Print Network (OSTI)

A DISTRIBUTION MEDIUM AND LOW VOLTAGE HV circuit breakers #12;©ABBGroup-4- 3-Sep-07 When a breaker fails to interrupt the current... Fault arc at a disconnector Fault arc in a substation #12;©ABBGroup-5- 3-Sep-07/costs A detailed understanding of arc physics and fluid dynamics is necessary for the development of HV circuit

Basse, Nils Plesner

148

Current vs. Voltage Feedback Amplifiers  

E-Print Network (OSTI)

?' In most applications, the differences between current feedback (CFB) and voltage feedback (VFB) are not apparent. Today's CFB and VFB amplifiers have comparable performance, but there are cer- tain unique Performance · Feedback Freedom Aside from the well-known attribute of CFB amplifiers, gain

Lanterman, Aaron

149

Modulated voltage metastable ionization detector  

SciTech Connect

Metastable ionization detectors used for chromatographic analysis usually employa fixed high voltage for the ionization potential. For this reason, the operating range is limited to about three orders of magnitude. By use of the technique disclosed in the instant invention, operating ranges of about nine orders of magnitude are obtained. The output current from a metastable ionization detector (MID) is applied to a modulation voltage circuit. An adjustment is made to balance out the background current, and an output current, above background, is applied to an input of a strip chart recorder. For low level concentrations, i.e., low detected output current, the ionization potential will be at a maximum and the metastable ionization detector will operate at its most sensitive level. When the detected current from the metastable ionization detector increases above a predetermined threshold level, a voltage control circuit is activated which turns on a high voltage transistor which acts to reduce the ionization potential. The ionization potential applied to the metastable ionization detector is then varied so as to maintain the detected signal level constant. The variation in ionization potential is now related to the concentration fo the constituent and a representative amplitude is applied to another input of said strip chart recorder.

Carle, G. C.; Humphry, D. E.; Kojiro, D. R.

1985-08-27T23:59:59.000Z

150

Frequency–dependent numerical dynamics in mosquitofish  

Science Journals Connector (OSTI)

...can invade, but not drive the others extinct...equilibrium of genotype frequencies and total numbers...replication in the low-frequency treatment because the...treatment to be more variable. Mesocosms were established...from throw-trap data Frequency-dependent numerical...

2002-01-01T23:59:59.000Z

151

Laser Doppler vibrometer employing active frequency feedback  

SciTech Connect

We present a heterodyne Michelson interferometer for vibration measurement in which feedback is used to obviate the need to unwrap phase data. The Doppler shift of a vibrating target mirror is sensed interferometrically and compensated by means of a voltage-controlled oscillator driving an acousto-optic modulator. For frequencies within the servo bandwidth, the oscillator control voltage provides a direct measurement of the target velocity. Outside the servo bandwidth, phase-sensitive detection is used to evaluate high-frequency displacements. This approach is of great interest for the frequently-occurring situation where vibration amplitudes at low frequency exceed an optical wavelength, but knowledge of the vibration spectrum at high frequency is important as well.

Chijioke, Akobuije; Lawall, John

2008-09-20T23:59:59.000Z

152

Automatic Voltage Control of Electrical Systems  

Science Journals Connector (OSTI)

... to have complete automatic voltage regulation and it also has supervisory control for its main substations. By a careful application of automatically controlled regulators it is shown that the voltage ...

1934-01-20T23:59:59.000Z

153

Implications of Pulser Voltage Ripple  

SciTech Connect

In a recent set of measurements obtained by G. Kamin, W. Manning, A. Molvik, and J. Sullivan, the voltage waveform of the diode pulser had a ripple of approximately {+-}1.3% of the 65 kV flattop voltage, and the beam current had a larger corresponding ripple of approximately {+-}8.4% of the 1.5 mA average current at the location of the second Faraday cup, approximately 1.9 m downstream from the ion source. The period of the ripple was about 1 {mu}s. It was initially unclear whether this large current ripple was in fact a true measurement of the current or a spurious measurement of noise produced by the pulser electronics. The purpose of this note is to provide simulations which closely match the experimental results and thereby corroborate the physical nature of those measurements, and to provide predictions of the amplitude of the current ripples as they propagate to the end of linear transport section. Additionally analytic estimates are obtained which lend some insight into the nature of the current fluctuations and to provide an estimate of what the maximum amplitude of the current fluctuations are expected to be, and conversely what initial ripple in the voltage source is allowed, given a smaller acceptable tolerance on the line charge density.

Barnard, J J

2011-12-21T23:59:59.000Z

154

Onset voltage of corona on coated conductors  

SciTech Connect

This paper is aimed for investigating the effect of surface coating on the positive and negative onset voltages of corona from stressed conductor as a pre-requisite for onset-voltage calculation. The electric field is accurately calculated by the charge simulation technique. The calculated onset voltages agreed satisfactorily with those measured experimentally for bare conductors. The effect of coating-layer thickness and permittivity as well as conductor radius and height on the onset-voltage values is discussed.

Abdel-Salam, M. [Assiut Univ. (Egypt). Electrical Engineering Dept.; Abo-Shal, Y. [SCECO-East, Dammam (Saudi Arabia). Electrical Engineering Div.

1995-12-31T23:59:59.000Z

155

Variable susceptance excitation control for dynamic performance improvement of a stand-alone wind turbine induction generator system  

Science Journals Connector (OSTI)

Isolated wind farms employ simple squirrel cage induction generators driven by variable speed wind turbines. Lacking control capability, such generation can contribute very little to network support. Wind turbines mostly do not take part in voltage and frequency control and if a disturbance occurs, the turbines may be disconnected and reconnected when normal operation has been resumed. From operation viewpoint, this is definitely not acceptable. A primary reason for the rigidity of operation is the lack of excitation adaptation under variable wind conditions. This article proposes incorporation of a variable capacitance controller at the generator terminal which will automatically adjust the needed excitation. Further improvement of transient profile of the stand-alone wind turbine generator has been proposed through inclusion of additional stabilising control. Simulation studies show that the proposed excitation controller with additional PID circuit provides very good transient profile following reasonable input torque variations.

A.H.M.A. Rahim; M. Ahsanul Alam

2009-01-01T23:59:59.000Z

156

Gene Frequency  

NLE Websites -- All DOE Office Websites (Extended Search)

Gene Frequency Gene Frequency Name: donna Location: N/A Country: N/A Date: N/A Question: If six fingers is a dominant human trait why do we have only five? Replies: This is simple. There are just not many genes in the human population for six fingers. Steve Sample Look in any high school biology book for what is known as Hardy-Weinberg equilibrium. These two scientists (separately) said that gene frequencies do not change much unless something in the environment selects them over other genes. In other words, unless 6 fingers somehow becomes an advantage, and five-fingered people have less of an advantage, the frequency of six fingered people in the population will not necessarily increase. This is the same reason that recessive traits don't disappear from the population. Also, six fingers is not considered attractive and they may not get as many mates. Also, more people are born with six fingers than you might imagine but just have them amputated shortly after birth.

157

6 - Control systems for AC variable speed drives  

Science Journals Connector (OSTI)

Publisher Summary This chapter explores the control system, embodied in the control circuits. The simplest method of providing auxiliary power to the converter control circuits is from an auxiliary transformer connected to the mains. The primary need for current feedback in general purpose variable speed drives (VSDs) is inverter switching device protection. Various disadvantages of the vector controlled AC drive as compared to a DC drive are discussed in the chapter. The strategy of an AC vector control drive is to calculate the individual current vectors to eventually enable separate control of the flux current and the torque current under all speed and load conditions. The power circuit for a vector converter is almost identical to that used by a variable voltage variable frequency (VVVF) drive. High accuracy motor current feedback is also necessary to provide control of motor torque. DC bus current feedback is suitable for switching device protection and current limiting in most AC VSDs. Analog speed transducers are increasingly being replaced by digital devices, which are more compatible with modern digital control systems.

Malcolm Barnes

2003-01-01T23:59:59.000Z

158

A theoretical study of the incandescent filament lamp performance under voltage flicker  

SciTech Connect

Incandescent filament lamp flicker, produced by voltage fluctuation, is a power quality problem that caused engineering concern since the onset of electrical illumination technology. The flicker phenomenon was analyzed and explained in early studies. Standards dealing with acceptable flicker levels are well known, nevertheless, today the discussion about flicker continues to be a top priority topic due to the fact that steady-state and transient voltage waveform distortion is a growing problem in low and medium voltage systems. In many situations voltage flicker is caused by subharmonics and interharmonics of voltage. Cycloconverters, welders and arc furnaces, eccentrically operating tools and integral cycle controlled power equipment are notorious for producing voltage flicker. The goal of this paper is to provide solid mathematical basis for the analytical modeling of incandescent filament lamp flicker when the voltage is nonsinusoidal. A mathematical model that enables the evaluation of the luminous flux modulation caused by noninteger harmonics (subharmonics and interharmonics) is presented. Three situations are detailed: square-wave voltage modulation, sinusoidal modulation and the case of noninteger harmonics with nearly contiguous frequencies.

Peretto, L. [Univ. of Bologna (Italy)] [Univ. of Bologna (Italy); Emanuel, A.E. [Worcester Polytechnic Inst., MA (United States)] [Worcester Polytechnic Inst., MA (United States)

1997-01-01T23:59:59.000Z

159

Variable current speed controller for eddy current motors  

DOE Patents (OSTI)

A speed control system for eddy current motors is provided in which the current to the motor from a constant frequency power source is varied by comparing the actual motor speed signal with a setpoint speed signal to control the motor speed according to the selected setpoint speed. A three-phase variable voltage autotransformer is provided for controlling the voltage from a three-phase power supply. A corresponding plurality of current control resistors is provided in series with each phase of the autotransformer output connected to inputs of a three-phase motor. Each resistor is connected in parallel with a set of normally closed contacts of plurality of relays which are operated by control logic. A logic circuit compares the selected speed with the actual motor speed obtained from a digital tachometer monitoring the motor spindle speed and operated the relays to add or substract resistance equally in each phase of the motor input to vary the motor current to control the motor at the selected speed.

Gerth, H.L.; Bailey, J.M.; Casstevens, J.M.; Dixon, J.H.; Griffith, B.O.; Igou, R.E.

1982-03-12T23:59:59.000Z

160

Wide band stepped frequency ground penetrating radar  

DOE Patents (OSTI)

A wide band ground penetrating radar system (10) embodying a method wherein a series of radio frequency signals (60) is produced by a single radio frequency source (16) and provided to a transmit antenna (26) for transmission to a target (54) and reflection therefrom to a receive antenna (28). A phase modulator (18) modulates those portion of the radio frequency signals (62) to be transmitted and the reflected modulated signal (62) is combined in a mixer (34) with the original radio frequency signal (60) to produce a resultant signal (53) which is demodulated to produce a series of direct current voltage signals (66) the envelope of which forms a cosine wave shaped plot (68) which is processed by a Fast Fourier Transform unit 44 into frequency domain data (70) wherein the position of a preponderant frequency is indicative of distance to the target (54) and magnitude is indicative of the signature of the target (54).

Bashforth, Michael B. (Buellton, CA); Gardner, Duane (Santa Maria, CA); Patrick, Douglas (Santa Maria, CA); Lewallen, Tricia A. (Ventura, CA); Nammath, Sharyn R. (Santa Barbara, CA); Painter, Kelly D. (Goleta, CA); Vadnais, Kenneth G. (Alexandria, VA)

1996-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "frequency variable voltage" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


161

Electrical power inverter having a phase modulated, twin-inverter, high frequency link and an energy storage module  

DOE Patents (OSTI)

The present invention provides an electrical power inverter method and apparatus, which includes a high frequency link, for converting DC power into AC power. Generally stated, the apparatus includes a first high frequency module which produces an AC voltage at a first output frequency, and a second high frequency inverter module which produces an AC voltage at a second output frequency that is substantially the same as the first output frequency. The second AC voltage is out of phase with the first AC voltage by a selected angular phase displacement. A mixer mixes the first and second output voltages to produce a high frequency carrier which has a selected base frequency impressed on the sidebands thereof. A rectifier rectifies the carrier, and a filter filters the rectified carrier. An output inverter inverts the filtered carrier to produce an AC line voltage at the selected base frequency. A phase modulator adjusts the relative angular phase displacement between the outputs of the first and second high frequency modules to control the base frequency and magnitude of the AC line voltage. 19 figs.

Pitel, I.J.

1987-02-03T23:59:59.000Z

162

Electrical power inverter having a phase modulated, twin-inverter, high frequency link and an energy storage module  

DOE Patents (OSTI)

The present invention provides an electrical power inverter method and apparatus, which includes a high frequency link, for converting DC power into AC power. Generally stated, the apparatus includes a first high frequency module which produces an AC voltage at a first output frequency, and a second high frequency inverter module which produces an AC voltage at a second output frequency that is substantially the same as the first output frequency. The second AC voltage is out of phase with the first AC voltage by a selected angular phase displacement. A mixer mixes the first and second output voltages to produce a high frequency carrier which has a selected base frequency impressed on the sidebands thereof. A rectifier rectifies the carrier, and a filter filters the rectified carrier. An output inverter inverts the filtered carrier to produce an AC line voltage at the selected base frequency. A phase modulator adjusts the relative angular phase displacement between the outputs of the first and second high frequency modules to control the base frequency and magnitude of the AC line voltage.

Pitel, Ira J. (Whippany, NJ)

1987-02-03T23:59:59.000Z

163

Definition: Operating Voltage | Open Energy Information  

Open Energy Info (EERE)

Voltage Voltage Jump to: navigation, search Dictionary.png Operating Voltage The voltage level by which an electrical system is designated and to which certain operating characteristics of the system are related; also, the effective (root-mean-square) potential difference between any two conductors or between a conductor and the ground. The actual voltage of the circuit may vary somewhat above or below this value.[1] Related Terms system References ↑ Glossary of Terms Used in Reliability Standards An LikeLike UnlikeLike You like this.Sign Up to see what your friends like. inline Glossary Definition Retrieved from "http://en.openei.org/w/index.php?title=Definition:Operating_Voltage&oldid=480559" Categories: Definitions ISGAN Definitions What links here Related changes

164

High voltage load resistor array  

DOE Patents (OSTI)

A high voltage resistor comprising an array of a plurality of parallel electrically connected resistor elements each containing a resistive solution, attached at each end thereof to an end plate, and about the circumference of each of the end plates, a corona reduction ring. Each of the resistor elements comprises an insulating tube having an electrode inserted into each end thereof and held in position by one or more hose clamps about the outer periphery of the insulating tube. According to a preferred embodiment, the electrode is fabricated from stainless steel and has a mushroom shape at one end, that inserted into the tube, and a flat end for engagement with the end plates that provides connection of the resistor array and with a load.

Lehmann, Monty Ray (Smithfield, VA)

2005-01-18T23:59:59.000Z

165

High-voltage R-F feedthrough bushing  

DOE Patents (OSTI)

Described is a multi-element, high voltage radio frequency bushing for transmitting rf energy to an antenna located in a vacuum container. The bushing includes a center conductor of complex geometrical shape, an outer coaxial shield conductor, and a thin-walled hollow truncated cone insulator disposed between central and outer conductors. The shape of the center conductor, which includes a reverse curvature portion formed of a radially inwardly directed shoulder and a convex portion, controls the uniformity of the axial surface gradient on the insulator cone. The outer shield has a first substantially cylindrical portion and a second radially inwardly extending truncated cone portion.

Grotz, G.F.

1982-09-03T23:59:59.000Z

166

Group 3: Humidity, Temperature, and Voltage (Presentation)  

SciTech Connect

Group 3 is chartered to develop accelerated stress tests that can be used as comparative predictors of module lifetime versus stresses associated with humidity, temperature and voltage.

Wohlgemuth, J.

2013-05-01T23:59:59.000Z

167

High Voltage Electrolyte for Lithium Batteries  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

battery using high voltage high energy cathode materials to enable large-scale, cost competitive production of the next generation of electric-drive vehicles. To...

168

Electrical aging of stator insulation of low voltage rotating machines supplied by inverters  

SciTech Connect

Nowadays, use of inverters for speed variation of low voltage motors becomes more and more usual. The most common technology for this kind of apparatus uses the Pulse Width Modulation (PWM). It is characterized by a square voltage shape with short rise and fall times. In order to insure the quality of turn to ground insulation submitted to these constraints, a study on the aging of Polyethylene terephthalate (Mylar{trademark}) has been undertaken. Influence of rise and fall times, frequency and voltage magnitude has been investigated for time duration up to 1,000 hours. To realize a good voltage application, samples were previously metalized. Two different behaviors according to the rise time and magnitude are observed. For long rise and fall times, changes in the capacity values are obtained although, for smaller rise or fall times, a degradation of the metalized electrode appears. A surface charge generation process is discussed to explain this phenomena.

Bellomo, J.P.; Lebey, T. [Lab. Genie Electrique de Toulouse (France); Oraison, J.M.; Peltier, F. [Leroy-Somer, Angouleme (France)

1996-12-31T23:59:59.000Z

169

Determining Hydrological Controls on Flood Frequency | U.S. DOE...  

NLE Websites -- All DOE Office Websites (Extended Search)

increasing aridity, variability increases. In contrast, BFI was found to exert a second-order control on flood frequency. Higher BFI, meaning higher contributions of subsurface...

170

Strongly nonlinear dynamics of electrolytes in large ac voltages Laurits Hjgaard Olesen,1,2  

E-Print Network (OSTI)

the results have been developed for over a century 1 . Current applications include energy storage; published 2 July 2010 We study the response of a model microelectrochemical cell to a large ac voltage of frequency comparable to the inverse cell relaxation time. To bring out the basic physics, we consider

171

Small-Signal Modeling of a Three-Phase Isolated Inverter with Both Voltage and  

E-Print Network (OSTI)

with the introduction of modern power generating units such as wind and solar power plants. As these new energy sourcesSmall-Signal Modeling of a Three-Phase Isolated Inverter with Both Voltage and Frequency Droop Rolla, Missouri 65409 Abstract-- In conventional power system operation, droop control methods are used

Kimball, Jonathan W.

172

DESIGN AND IMPLEMENTATION OF A FUZZY LOGIC-BASED VOLTAGE CONTROLLER FOR VOLTAGE REGULATION  

E-Print Network (OSTI)

1 DESIGN AND IMPLEMENTATION OF A FUZZY LOGIC-BASED VOLTAGE CONTROLLER FOR VOLTAGE REGULATION In this paper the design and implementation of a fuzzy logic-based controller is described for regulating the output voltage of a synchronous generator. An automated fuzzy logic-based control strategy is presented

LaMeres, Brock J.

173

Efficient Computation of Sensitivity Coefficients of Node Voltages and Line Currents in Unbalanced Electrical Networks  

E-Print Network (OSTI)

The problem of optimal control of power distribution systems is becoming increasingly compelling due to the progressive penetration of distributed energy resources in this specific layer of the electrical infrastructure. Distribution systems are, indeed, experiencing significant changes in terms of operation philosophies that are often based on optimal control strategies relying on the computation of linearized dependencies between controlled (e.g. voltages) and control variables (e.g. power injections). As the implementation of these strategies in real-time controllers imposes stringent time constraints, the derivation of analytical dependency between controlled and control variables becomes a non-trivial task to be solved. With reference to optimal voltage and power flow controls, this paper aims at providing an analytical derivation of node voltage and line current flows as a function of the nodal power injections. Compared to other approaches presented in the literature, the one proposed here is based on ...

Christakou, Konstantina; Paolone, Mario; Tomozei, Dan-Cristian

2012-01-01T23:59:59.000Z

174

Development of High Voltage Electron Microscope  

Science Journals Connector (OSTI)

......Cockcroft Walton Type High Voltage Generator. O Power Line O Fig. 4...pressure in the tank to the atmospheric pressure by removing freon...pump using liquid nitrogen. Water buffer and liquid nitrogen...base plate of high voltage generator. Four poles stand on this......

Shinjiro KATAGIRI; Hirokazu KIMURA; Susumu OZASA; Kazumi SHIRAISHI

1969-01-01T23:59:59.000Z

175

Voltage regulation in linear induction accelerators  

DOE Patents (OSTI)

Improvement in voltage regulation in a Linear Induction Accelerator wherein a varistor, such as a metal oxide varistor, is placed in parallel with the beam accelerating cavity and the magnetic core. The non-linear properties of the varistor result in a more stable voltage across the beam accelerating cavity than with a conventional compensating resistance.

Parsons, William M. (Santa Fe, NM)

1992-01-01T23:59:59.000Z

176

Voltage regulation in linear induction accelerators  

DOE Patents (OSTI)

Improvement in voltage regulation in a linear induction accelerator wherein a varistor, such as a metal oxide varistor, is placed in parallel with the beam accelerating cavity and the magnetic core is disclosed. The non-linear properties of the varistor result in a more stable voltage across the beam accelerating cavity than with a conventional compensating resistance. 4 figs.

Parsons, W.M.

1992-12-29T23:59:59.000Z

177

Limitations of High-Voltage Insulation  

Science Journals Connector (OSTI)

... materials such as impregnated paper. The important electrical properties of the materials used for the insulation of high-voltage circuits are conductivity and electric strength. The conductivity measures the ability ... a million times between themselves, but they are all classified as available for high-voltage insulation.

1938-01-08T23:59:59.000Z

178

NREL: Measurements and Characterization - Current Versus Voltage  

NLE Websites -- All DOE Office Websites (Extended Search)

Current Versus Voltage Current Versus Voltage The National Renewable Energy Laboratory (NREL) Device Performance group uses current versus voltage (I-V) measurement systems to assess the main performance parameters for photovoltaic (PV) cells and modules. I-V measurement systems determine the output performance of devices, including: open-circuit voltage (Voc), short-circuit current (Isc), fill factor (FF), maximum power output of the device (Pmax), voltage at maximum power (Vmax), current at maximum power (Imax), and conversion efficiency of the device (η). Some I-V systems may also be used to perform dark I-V measurements to determine diode properties and series and shunt resistances. We use three I-V systems to measure performance of individual PV cells; and four for modules - two for measurements under simulated conditions; and

179

High Voltage Safety Act | Department of Energy  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

High Voltage Safety Act High Voltage Safety Act High Voltage Safety Act < Back Eligibility Commercial Construction Developer General Public/Consumer Industrial Installer/Contractor Utility Savings Category Alternative Fuel Vehicles Hydrogen & Fuel Cells Buying & Making Electricity Water Home Weatherization Solar Wind Program Info State Georgia Program Type Safety and Operational Guidelines Siting and Permitting The purpose of the High Voltage Safety Act is to prevent injury to persons and property and interruptions of utility service resulting from accidental or inadvertent contact with high-voltage electric lines by providing that no work shall be done in the vicinity of such lines unless and until the owner or operator thereof has been notified of such work and has taken the appropriate safety measures. The Georgia Public Service Commission requires

180

Non-contact current and voltage sensor  

DOE Patents (OSTI)

A detachable current and voltage sensor provides an isolated and convenient device to measure current passing through a conductor such as an AC branch circuit wire, as well as providing an indication of an electrostatic potential on the wire, which can be used to indicate the phase of the voltage on the wire, and optionally a magnitude of the voltage. The device includes a housing that contains the current and voltage sensors, which may be a ferrite cylinder with a hall effect sensor disposed in a gap along the circumference to measure current, or alternative a winding provided through the cylinder along its axis and a capacitive plate or wire disposed adjacent to, or within, the ferrite cylinder to provide the indication of the voltage.

Carpenter, Gary D; El-Essawy, Wael; Ferreira, Alexandre Peixoto; Keller, Thomas Walter; Rubio, Juan C; Schappert, Michael A

2014-03-25T23:59:59.000Z

Note: This page contains sample records for the topic "frequency variable voltage" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


181

Amplitude modulation free, wide band frequency modulated oscillator  

E-Print Network (OSTI)

oscillator- - - - - ? ? - ? 3 15 ~ Iiide Bmd Frc saency Lodulator Relatively Free of A@elf tude Modulation-? ? 35 1~'i. Tank Uoltare Versus Fx~tuency or . 'evcral Loads ? - ? ? - 35 17. Screon Voltage Versus Frequency? 10. Amclitude Lodulafion Envelope... of Conventional Design- - ? 39 19 ' ~litude Ltodulation Eave" ope of !iem Design- - - ? - - ? 39 20. Tank Voltage Versus 11~-, coney of Conventisnal Design Hew Design INTRODUCTION The accurate and rapid determination and location of faults is very important...

Nelson, Dick Frank

1951-01-01T23:59:59.000Z

182

3D MHD modelling of the glidarc behaviour of a low current high voltage DC plasma torch Journal of Physics D: Applied Physics  

E-Print Network (OSTI)

in terms of: global behaviour, arc length, mean voltage and glidarc frequency. 1. Introduction The non-thermal on magnetohydrodynamic (MHD) modelling of atmospheric pressure direct current (DC) plasma torch operating at low current3D MHD modelling of the glidarc behaviour of a low current ­ high voltage DC plasma torch Journal

Paris-Sud XI, Université de

183

The driving frequency effects on the atmospheric pressure corona jet plasmas from low frequency to radio frequency  

Science Journals Connector (OSTI)

Lately the atmospheric pressure jet type coronaplasma which has been typically driven by dc to low frequency (LF: several tens of kHz) is often generated by using radio frequency of 13.56 MHz. Yet the relationship between the plasma and its driving frequency has seldom been investigated. Hence in this study dependence of the atmospheric pressurecoronaplasmacharacteristics on the driving frequency was explored experimentally from LF to rf (5 kHz–13.56 MHz). The plasmas generated by the driving frequency under 2 MHz were cylindrical shape of several tens of millimeters long while the 13.56 MHz plasma is spherical and a few millimeters long. As the driving frequency was increased the plasma length became shortened. At the lower driving frequencies (below 2 MHz) the plasmas existed as positive streamer and negative glow for each half period of the applied voltage but the discharge was more continuous in time for the 13.56 MHz plasma. It was inferred from the measured I–V curves that the higher driving frequency induced higher discharge currents and the gas temperature was increased as the driving frequency was increased.

Dan Bee Kim; H. Jung; B. Gweon; S. Y. Moon; J. K. Rhee; W. Choe

2011-01-01T23:59:59.000Z

184

Electro-optical voltage sensor head  

DOE Patents (OSTI)

A miniature electro-optic voltage sensor system capable of accurate operation at high voltages. The system employs a transmitter, a sensor disposed adjacent to but out of direct electrical contact with a conductor on which the voltage is to be measured, a detector, and a signal processor. The transmitter produces a beam of electromagnetic radiation which is routed into the sensor where the beam undergoes the Pockels electro-optic effect. The electro-optic effect causes phase shifting in the beam, which is in turn converted to a pair of independent beams, from which the voltage of a system based on its E-field is determined when the two beams are normalized by the signal processor. The sensor converts the beam by splitting the beam in accordance with the axes of the beam's polarization state (an ellipse whose ellipticity varies between -1 and +1 in proportion to voltage) into at least two AM signals. These AM signals are fed into a signal processor and processed to determine the voltage between a ground conductor and the conductor on which voltage is being measured.

Woods, Gregory K. (Idaho Falls, ID)

1998-01-01T23:59:59.000Z

185

Measurement of electron temperatures and electron energy distribution functions in dual frequency capacitively coupled CF4/O2 plasmas using  

E-Print Network (OSTI)

emission spectroscopy TRG-OES . The parallel plate etcher was powered by a high frequency 60 MHz "source frequency LF source, while the plasma density and ion flux are determined mainly by the high frequency HF-dimensional model of a 2f-CCP driven by the superposition of two sinusoidal radio-frequency rf voltages. They found

Economou, Demetre J.

186

Chapter Seven - Variable speed drives  

Science Journals Connector (OSTI)

Publisher Summary The electromechanical controllers are a kind of variable speed drives (VSDs) that are obsolete but are still in use because when a motor and a drive is combined, they become a power drive system (PDS). There are two ways of varying the speed of an induction motor, either by varying the motor slip or by varying the supply frequency. The preferred practice for electrical speed variation is to change the supply frequency with a variable frequency drive (VFD). Many other designs also have been developed. However, except the specialized applications, few are still in operation. A number of motor and drive manufacturers are now producing the integrated motor/VFD units. These units consist of a motor and a specially designed VFD, produced as a single package, with the VFD unit mounted variously on the top, side, or end of the motor.

Europump; Hydraulic Institute

2005-01-01T23:59:59.000Z

187

Performance Variability  

NLE Websites -- All DOE Office Websites (Extended Search)

Variability Variability of Highly Parallel Architectures William T.C. Kramer 1 and Clint Ryan 2 1 Department of Computing Sciences, University of California at Berkeley and the National Energy Research Scientific Computing Center, Lawrence Berkeley National Laboratory 2 Department of Computing Sciences, University of California at Berkeley Abstract. The design and evaluation of high performance computers has concentrated on increasing computational speed for applications. This performance is often measured on a well configured dedicated sys- tem to show the best case. In the real environment, resources are not always dedicated to a single task, and systems run tasks that may influ- ence each other, so run times vary, sometimes to an unreasonably large extent. This paper explores the amount of variation seen across four large distributed memory systems in a systematic manner. It then

188

Researchers map atomic movements that trigger voltage fade in...  

NLE Websites -- All DOE Office Websites (Extended Search)

map atomic movements that trigger voltage fade in high-energy-density batteries January 22, 2015 Voltage and capacity curves from an LMR-NMC high-energy cathode show voltage fade...

189

Characterization of arcs in frequency domain  

SciTech Connect

Arc detection systems are developed for ICRH on ITER to prevent arcs from damaging the RF components. One of the detectors, the Sub-Harmonic Arc Detector (SHAD) is based on the detection of the frequencies emitted in the MHz range by arcs [R1]. To ensure the high level of reliability required for this safety system, it is necessary to demonstrate that these frequencies present a signal with a Signal to Noise Ratio high enough to be detected under the wide range of operational conditions (frequency, power, configuration) and for the different types of arcs that can appear in the feeding lines and on the antennas (vacuum arc, glow discharge, multipactor-induced discharge). For each type of arc, we analyze the evolution of the frequency spectrum relative to the evolution of other electrical parameters (reflected power, voltage)

D'Inca, R.; Siegl, G.; Faugel, H.; Braun, F.; Eckert, B.; Bobkov, V. [Max Planck Institut fuer Plasmaphysik, Garching, Germany, EURATOM Association (Germany); El Khaldi, M. [CEA, IRFM, F-13108 Saint-Paul-lez-Durance (France); Noterdaeme, J.-M. [Max Planck Institut fuer Plasmaphysik, Garching, Germany, EURATOM Association (Germany); Gent University, EESA Department (Belgium)

2009-11-26T23:59:59.000Z

190

Property:Nominal Voltage | Open Energy Information  

Open Energy Info (EERE)

Nominal Voltage Nominal Voltage Jump to: navigation, search Property Name Nominal Voltage Property Type Number This is a property of type Number. Pages using the property "Nominal Voltage" Showing 22 pages using this property. D Distributed Generation Study/10 West 66th Street Corp + 480 + Distributed Generation Study/615 kW Waukesha Packaged System + 480 + Distributed Generation Study/Aisin Seiki G60 at Hooligans Bar and Grille + 240 + Distributed Generation Study/Arrow Linen + 480 + Distributed Generation Study/Dakota Station (Minnegasco) + 0 + Distributed Generation Study/Elgin Community College + 4,160 + Distributed Generation Study/Emerling Farm + 480 + Distributed Generation Study/Floyd Bennett + 480 + Distributed Generation Study/Harbec Plastics + 480 +

191

Low voltage arc formation in railguns  

DOE Patents (OSTI)

A low voltage plasma arc is first established across the rails behind the projectile by switching a low voltage high current source across the rails to establish a plasma arc by vaporizing a fuse mounted on the back of the projectile, maintaining the voltage across the rails below the railgun breakdown voltage to prevent arc formation ahead of the projectile. After the plasma arc has been formed behind the projectile a discriminator switches the full energy bank across the rails to accelerate the projectile. A gas gun injector may be utilized to inject a projectile into the breech of a railgun. The invention permits the use of a gas gun or gun powder injector and an evacuated barrel without the risk of spurious arc formation in front of the projectile.

Hawke, R.S.

1985-08-05T23:59:59.000Z

192

Low voltage arc formation in railguns  

DOE Patents (OSTI)

A low voltage plasma arc is first established across the rails behind the projectile by switching a low voltage high current source across the rails to establish a plasma arc by vaporizing a fuse mounted on the back of the projectile, maintaining the voltage across the rails below the railgun breakdown voltage to prevent arc formation ahead of the projectile. After the plasma arc has been formed behind the projectile a discriminator switches the full energy bank across the rails to accelerate the projectile. A gas gun injector may be utilized to inject a projectile into the breech of a railgun. The invention permits the use of a gas gun or gun powder injector and an evacuated barrel without the risk of spurious arc formation in front of the projectile. 2 figs.

Hawke, R.S.

1987-11-17T23:59:59.000Z

193

Low voltage arc formation in railguns  

DOE Patents (OSTI)

A low voltage plasma arc is first established across the rails behind the projectile by switching a low voltage high current source across the rails to establish a plasma arc by vaporizing a fuse mounted on the back of the projectile, maintaining the voltage across the rails below the railgun breakdown voltage to prevent arc formation ahead of the projectile. After the plasma arc has been formed behind the projectile a discriminator switches the full energy bank across the rails to accelerate the projectile. A gas gun injector may be utilized to inject a projectile into the breech of a railgun. The invention permits the use of a gas gun or gun powder injector and an evacuated barrel without the risk of spurious arc formation in front of the projectile.

Hawke, Ronald S. (Livermore, CA)

1987-01-01T23:59:59.000Z

194

A system for tranmitting low frequency analog signals over ac power lines  

DOE Patents (OSTI)

A system for transmitting low frequency analog signals over ac power lines using FM modulation. A low frequency analog signal to be transmitted is first applied to a voltage-to-frequency converter where it is converted to a signal whose frequency varies in proportion to the analog signal amplitude. This signal is then used to modulate the carrier frequency of an FM transmitter coupled to an ac power line. The modulation signal frequency range is selected to be within the response band of the FM transmitter. The FM modulated carrier signal is received by an FM receiver coupled to the ac power line, demodulated and the demodulated signal frequency is converted by a frequency-to-voltage converter back to the form of the original low frequency analog input signal. 4 figs.

Baker, S.P.; Durall, R.L.; Haynes, H.D.

1987-07-30T23:59:59.000Z

195

System for transmitting low frequency analog signals over AC power lines  

DOE Patents (OSTI)

A system for transmitting low frequency analog signals over AC power lines using FM modulation. A low frequency analog signal to be transmitted is first applied to a voltage-to-frequency converter where it is converted to a signal whose frequency varies in proportion to the analog signal amplitude. This signal is then used to modulate the carrier frequency of an FM transmitter coupled to an AC power line. The modulation signal frequency range in selected to be within the response band of the FM transmitter. The FM modulated carrier signal is received by an FM receiver coupled to the AC power line, demodulated and the demodulated signal frequency is converted by a frequency-to-voltage converter back to the form of the original low frequency analog input signal.

Baker, Steven P. (Powell, TN); Durall, Robert L. (Lenoir City, TN); Haynes, Howard D. (Knoxville, TN)

1989-01-01T23:59:59.000Z

196

Modular high voltage power supply for chemical analysis  

DOE Patents (OSTI)

A high voltage power supply for use in a system such as a microfluidics system, uses a DC-DC converter in parallel with a voltage-controlled resistor. A feedback circuit provides a control signal for the DC-DC converter and voltage-controlled resistor so as to regulate the output voltage of the high voltage power supply, as well as, to sink or source current from the high voltage supply.

Stamps, James F. (Livermore, CA); Yee, Daniel D. (Dublin, CA)

2010-05-04T23:59:59.000Z

197

Constant voltage electro-slag remelting control  

DOE Patents (OSTI)

A system for controlling electrode gap in an electro-slag remelt furnace has a constant regulated voltage and an electrode which is fed into the slag pool at a constant rate. The impedance of the circuit through the slag pool is directly proportional to the gap distance. Because of the constant voltage, the system current changes are inversely proportional to changes in gap. This negative feedback causes the gap to remain stable. 1 fig.

Schlienger, M.E.

1996-10-22T23:59:59.000Z

198

Vehicle Technologies Office Merit Review 2014: High-Voltage Solid...  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

High-Voltage Solid Polymer Batteries for Electric Drive Vehicles Vehicle Technologies Office Merit Review 2014: High-Voltage Solid Polymer Batteries for Electric Drive Vehicles...

199

High-Voltage Solid Polymer Batteries for Electric Drive Vehicles...  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

High-Voltage Solid Polymer Batteries for Electric Drive Vehicles High-Voltage Solid Polymer Batteries for Electric Drive Vehicles 2013 DOE Hydrogen and Fuel Cells Program and...

200

High-Voltage Solid Polymer Batteries for Electric Drive Vehicles...  

Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

High-Voltage Solid Polymer Batteries for Electric Drive Vehicles High-Voltage Solid Polymer Batteries for Electric Drive Vehicles 2012 DOE Hydrogen and Fuel Cells Program and...

Note: This page contains sample records for the topic "frequency variable voltage" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


201

Cathode Synthesis and Voltage Fade: Designed Solutions Based...  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Cathode Synthesis and Voltage Fade: Designed Solutions Based on Theory Cathode Synthesis and Voltage Fade: Designed Solutions Based on Theory 2013 DOE Hydrogen and Fuel Cells...

202

Optimal Voltage Control of the Southern Norwegian Power Grid.  

E-Print Network (OSTI)

??This thesis contains the synthesis, analysis and simulation results of an automatic optimal voltage controller for the Southern Norwegian power grid. Currently the high voltage… (more)

Hannisdal, Erik Lundegaard

2011-01-01T23:59:59.000Z

203

Addressing the Voltage Fade Issue with Lithium-Manganese-Rich...  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Addressing the Voltage Fade Issue with Lithium-Manganese-Rich Oxide Cathode Materials Addressing the Voltage Fade Issue with Lithium-Manganese-Rich Oxide Cathode Materials 2013 DOE...

204

High voltage overhead long transmission line design and fault analysis.  

E-Print Network (OSTI)

??The goal of this project is to design a reliable high voltage overhead long transmission line that satisfies specific design criteria including voltage regulation, efficiency,… (more)

Elzain, Mohamed Ali

2011-01-01T23:59:59.000Z

205

Soft-Switching High-Frequency AC-Link Universal Power Converters with Galvanic Isolation  

E-Print Network (OSTI)

be used in a variety of applications, including photovoltaic power generation, wind power generation, and electric vehicles. In these converters the link current and voltage are both alternating and their frequency can be high, which leads...

Amirabadi, Mahshid

2013-08-07T23:59:59.000Z

206

Metal slits and liquid crystals at microwave frequencies  

Science Journals Connector (OSTI)

...the possible use of dual frequency materials to allow drive-on as well as drive-off. Unfortunately such dual-frequency materials have reduced...T Nomoto2002Microwave variable delay line using dual-frequency switching-mode liquid...

2006-01-01T23:59:59.000Z

207

High-frequency response and the possibilities of frequency-tunable narrow-band terahertz amplification in resonant tunneling nanostructures  

SciTech Connect

The characteristics of the high-frequency response of single- and double-well resonant tunneling structures in a dc electric field are investigated on the basis of the numerical solution of a time-dependent Schroedinger equation with open boundary conditions. The frequency dependence of the real part of high frequency conductivity (high-frequency response) in In{sub 0.53}Ga{sub 0.47}As/AlAs/InP structures is analyzed in detail for various values of the dc voltage V{sub dc} in the negative differential resistance (NDR) region. It is shown that double-well three-barrier structures are promising for the design of terahertz-band oscillators. The presence of two resonant states with close energies in such structures leads to a resonant (in frequency) response whose frequency is determined by the energy difference between these levels and can be controlled by varying the parameters of the structure. It is shown that, in principle, such structures admit narrow-band amplification, tuning of the amplification frequency, and a fine control of the amplification (oscillation) frequency in a wide range of terahertz frequencies by varying a dc electric voltage applied to the structure. Starting from a certain width of the central intermediate barrier in double-well structures, one can observe a collapse of resonances, where the structure behaves like a single-well system. This phenomenon imposes a lower limit on the oscillation frequency in three-barrier resonant tunneling structures.

Kapaev, V. V., E-mail: kapaev@sci.lebedev.ru; Kopaev, Yu. V.; Savinov, S. A.; Murzin, V. N. [Russian Academy of Sciences, Lebedev Physical Institute (Russian Federation)] [Russian Academy of Sciences, Lebedev Physical Institute (Russian Federation)

2013-03-15T23:59:59.000Z

208

Development of a quantum-voltage-calibrated noise thermometer at NIM  

SciTech Connect

A quantum-voltage-calibrated Johnson-noise thermometer was developed at NIM, which measures the Boltzmann constant k by comparing the thermal noise across a 100 ? sense resistor at the temperature of the triple point of water with the pseudo-random frequency-comb voltage waveform synthesized with a bipolar-pulse-driven quantum-voltage-noise source. A measurement with integration period of 10 hours and bandwidth of 640 kHz resulted in a relative offset of 0.5×10{sup ?6} from the current CODATA value of k, and a type A relative standard uncertainty of 23×10{sup ?6}. Benefiting from closely matched noise powers and transmission-line impedances and small nonlinearities in the cross-correlation electronics, the derived k shows self-consistent values and standard uncertainties for different measurement bandwidths.

Qu, J.; Zhang, J. T.; Fu, Y. [National Institute of Metrology, Beijing 100013, P. R. (China)] [National Institute of Metrology, Beijing 100013, P. R. (China); Rogalla, H.; Pollarolo, A.; Benz, S. P. [National Institute of Standards and Technology, Boulder, CO 80305 (United States)] [National Institute of Standards and Technology, Boulder, CO 80305 (United States)

2013-09-11T23:59:59.000Z

209

Distribution System Voltage Performance Analysis for High-Penetration Photovoltaics  

SciTech Connect

This report examines the performance of commonly used distribution voltage regulation methods under reverse power flow.

Liu, E.; Bebic, J.

2008-02-01T23:59:59.000Z

210

Voltage flicker prediction for two simultaneously operated ac arc furnaces  

SciTech Connect

An EMTP-based arc furnace model was developed for evaluation of flicker concerns associated with supplying a large integrated steel mill as they go from one to two furnace operation and as system changes are implemented that will affect the short circuit capacity at the 230 kV power supply substation. The model includes a dynamic arc representation which is designed to be characteristic of the initial portions of the melt cycle when the arc characteristics are the most variable (worst flicker conditions). The flicker calculations are verified using previous measurements with one furnace operation. Flicker simulations were then performed to evaluate a variety of different possible system strengths with both one and two furnaces in operation. The primary flicker measure used for this study is the unweighted rms value of the fluctuation envelope, expressed as a percentage of the rms line-to-ground voltage magnitude.

Tang, L. [ABB Power T and D Co., Inc., Raleigh, NC (United States)] [ABB Power T and D Co., Inc., Raleigh, NC (United States); Kolluri, S. [Entergy Services, New Orleans, LA (United States)] [Entergy Services, New Orleans, LA (United States); McGranaghan, M.F. [Electrotek Concepts, Inc., Knoxville, TN (United States)] [Electrotek Concepts, Inc., Knoxville, TN (United States)

1997-04-01T23:59:59.000Z

211

Gas breakdown in an atmospheric pressure radio-frequency capacitive plasma source  

Science Journals Connector (OSTI)

Gas breakdown is studied in an atmospheric pressure rf capacitive plasma source developed for materials applications. At a rf frequency of 13.56 MHz breakdown voltage is largely a function of the product of the pressure and the discharge gap spacing approximating the Paschen curve. However breakdown voltage varies substantially with rf frequency due to a change in the electron loss mechanism. A large increase in breakdown voltage is observed when argon oxygen or nitrogen is added to helium despite their lower ionization potential. Discussion is given for optimal breakdown conditions at atmospheric pressure.

Jaeyoung Park; I. Henins; H. W. Herrmann; G. S. Selwyn

2001-01-01T23:59:59.000Z

212

Physical simulation study of dynamic voltage instability  

SciTech Connect

This paper presents a physical simulation of the dynamic behavior of voltage instability in an interconnected multimachine environment. The dynamic evolving process leading to eventual voltage collapse, the scenario of the progressive reactive support reduction resulting from the MXL protection relays, the OLTC operation, and the effect of switched-in capacitor banks are examined using physical facilities in the laboratory. The physical simulation results are also compared with digital simulation results. This physical investigation provides a reliable foundation for the effective development of assessment approaches and countermeasures.

Tso, S.K.; Zhu, T.X. [Univ. of Hong Kong (Hong Kong); Zeng, Q.Y. [Electric Power Research Inst., Beijing (China); Lo, K.L. [Univ. of Strathclyde, Glasgow (United Kingdom). Dept. of Electrical and Electrical Engineering

1995-12-31T23:59:59.000Z

213

High frequency rectenna  

DOE Patents (OSTI)

The invention provides an inexpensive array of rectifying antennas which employ field emission diodes for rectifying electromagnetic waves of microwave frequencies and higher frequencies.

Logan, B. Grant (Danville, CA); Orvis, William J. (Livermore, CA)

1991-01-01T23:59:59.000Z

214

Numerical simulation of dual frequency etching reactors: Influence of the external process parameters on the plasma characteristics  

SciTech Connect

A one-dimensional particle-in-cell/Monte Carlo model is used to investigate Ar/CF{sub 4}/N{sub 2} discharges sustained in capacitively coupled dual frequency reactors, with special emphasis on the influence of the reactor parameters such as applied voltage amplitudes and frequencies of the two voltage sources. The presented calculation results include plasma density, ion current, average sheath potential and width, electron and ion average energies and energy distributions, and ionization rates. The simulations were carried out for high frequencies (HFs) of 27, 40, 60, and 100 MHz and a low frequency (LF) of 1 or 2 MHz, varying the LF voltage and keeping the HF voltage constant and vice versa. It is observed that the decoupling of the two sources is possible by increasing the applied HF to very high values (above 60 MHz) and it is not defined by the frequency ratio. Both voltage sources have influence on the plasma characteristics at a HF of 27 MHz and to some extent at 40 MHz. At HFs of 60 and 100 MHz, the plasma density and ion flux are determined only by the HF voltage source. The ion energy increases and the ion energy distribution function (IEDF) becomes broader with HF or LF voltage amplitude, when the other voltage is kept constant. The IEDF is broader with the increase of HF or the decrease of LF.

Georgieva, V.; Bogaerts, A. [Plasma, Laser Ablation and Surface Modeling ANTwerp (PLASMANT), Department of Chemistry, University of Antwerp, Campus Drie Eiken (CDE), Universiteitsplein 1, B-2610 Wilrijk-Antwerp (Belgium)

2005-07-15T23:59:59.000Z

215

Hedge-algebra-based voltage controller for a self-excited induction generator  

Science Journals Connector (OSTI)

Abstract This paper presents an indirect rotor-flux-oriented (IRFO) control system of the self-excited induction generator (SEIG) in which excitation is achieved by means of a current-controlled voltage source inverter (CC-VSI) and a single electrolytic capacitor. In the proposed control scheme, both the iron losses and the magnetic saturation are taken into account and calculated online. The main objective is to keep the DC voltage across the capacitor constant and equal to the reference value, regardless of changes in the rotor speed and load. The study is mainly focused on the DC voltage control and, more specifically, on selection of the appropriate DC voltage controller. Besides considering widely accepted types of controllers, i.e., the classical PI controller and the fuzzy logic (FL) controller, this paper proposes an alternative solution – a new type of DC voltage controller based on hedge algebra. To our best knowledge, this is the first time that such a controller is considered for application in electrical engineering. The performance of the developed hedge algebra (HA) controller is evaluated through comparison with the optimal-tuned classical PI controller and the Sugeno-type FL controller. The simulation and experimental analysis are carried out in reasonably wide ranges of the DC voltage, load and rotor speed, including the case of a variable rotor speed. It is shown that the proposed HA controller provides superior performance in terms of tracking the reference DC voltage value as well as robustness to speed and load disturbances in the system.

Dinko Vukadinovi?; Mateo Baši?; Cat Ho Nguyen; Nhu Lan Vu; Tien Duy Nguyen

2014-01-01T23:59:59.000Z

216

Electro-optic voltage sensor for sensing voltage in an E-field  

DOE Patents (OSTI)

A miniature electro-optic voltage sensor system capable of accurate operation at high voltages. The system employs a transmitter, a sensor disposed adjacent to but out of direct electrical contact with a conductor on which the voltage is to be measured, a detector, and a signal processor. The transmitter produces a beam of electromagnetic radiation which is routed into the sensor where the beam undergoes the Pockels electro-optic effect. The electro-optic effect causes phase shifting in the beam, which is in turn converted to a pair of independent beams, from which the voltage of a system based on its E-field is determined when the two beams are normalized by the signal processor. The sensor converts the beam by splitting the beam in accordance with the axes of the beam's polarization state (an ellipse whose ellipticity varies between -1 and +1 in proportion to voltage) into at least two AM signals. These AM signals are fed into a signal processor and processed to determine the voltage between a ground conductor and the conductor on which voltage is being measured.

Woods, Gregory K. (Idaho Falls, ID); Renak, Todd W. (Idaho Falls, ID)

1999-01-01T23:59:59.000Z

217

On the scaling of rf and dc self-bias voltages with pressure in electronegative capacitively coupled plasmas  

SciTech Connect

Higher gas densities and lower diffusion losses at higher operating pressures typically lead to increased charged species densities (and hence flux) for a constant power deposition in capacitively coupled plasmas (CCP). As a result, one would expect that the bias radio-frequency (rf) voltage required to deposit a given power in a CCP reactor decreases with increasing operating pressure. These observations may not hold true in multiple frequency CCPs, commonly used for dielectric etching in microelectronics fabrication, due to nonlinear interactions between the rf sources. Wafer-based measurements of the rf and self-generated direct current (dc) bias voltages in a dual-frequency capacitively coupled electronegative plasma were made, which indicate that the rf and dc voltages vary nonmonotonically with pressure. These experimental results are presented in this paper and a computational plasma model is used to explain the experimental observations for varying 60 MHz and 13 MHz powers in the Ar/CF{sub 4}/CHF{sub 3} plasma over a pressure range of 25 to 400 mTorr. The authors found that while the ion density increases with pressure, the increase is most dominant near the electrode with the high frequency source (60 MHz). The rf and dc bias voltages are ultimately influenced by both charged species density magnitudes and spatial profiles.

Agarwal, Ankur; Dorf, Leonid; Rauf, Shahid; Collins, Ken [Applied Materials Inc., 974 E. Arques Avenue, M/S 81312, Sunnyvale, California 94085 (United States)

2012-03-15T23:59:59.000Z

218

Extremely high frequency RF effects on electronics.  

SciTech Connect

The objective of this work was to understand the fundamental physics of extremely high frequency RF effects on electronics. To accomplish this objective, we produced models, conducted simulations, and performed measurements to identify the mechanisms of effects as frequency increases into the millimeter-wave regime. Our purpose was to answer the questions, 'What are the tradeoffs between coupling, transmission losses, and device responses as frequency increases?', and, 'How high in frequency do effects on electronic systems continue to occur?' Using full wave electromagnetics codes and a transmission-line/circuit code, we investigated how extremely high-frequency RF propagates on wires and printed circuit board traces. We investigated both field-to-wire coupling and direct illumination of printed circuit boards to determine the significant mechanisms for inducing currents at device terminals. We measured coupling to wires and attenuation along wires for comparison to the simulations, looking at plane-wave coupling as it launches modes onto single and multiconductor structures. We simulated the response of discrete and integrated circuit semiconductor devices to those high-frequency currents and voltages, using SGFramework, the open-source General-purpose Semiconductor Simulator (gss), and Sandia's Charon semiconductor device physics codes. This report documents our findings.

Loubriel, Guillermo Manuel; Vigliano, David; Coleman, Phillip Dale; Williams, Jeffery Thomas; Wouters, Gregg A.; Bacon, Larry Donald; Mar, Alan

2012-01-01T23:59:59.000Z

219

Distribution System Voltage Regulation by Distributed Energy Resources  

SciTech Connect

This paper proposes a control method to regulate voltages in 3 phase unbalanced electrical distribution systems. A constrained optimization problem to minimize voltage deviations and maximize distributed energy resource (DER) active power output is solved by harmony search algorithm. IEEE 13 Bus Distribution Test System was modified to test three different cases: a) only voltage regulator controlled system b) only DER controlled system and c) both voltage regulator and DER controlled system. The simulation results show that systems with both voltage regulators and DER control provide better voltage profile.

Ceylan, Oguzhan [ORNL; Liu, Guodong [ORNL; Xu, Yan [ORNL; Tomsovic, Kevin [University of Tennessee, Knoxville (UTK)

2014-01-01T23:59:59.000Z

220

Chapter 18: Variable Frequency Drive Evaluation Protocol. The...  

Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

by Pat Corkery, NREL 16560, photo by Dennis Schroeder, NREL 17613, photo by Dean Armstrong, NREL 17436, photo by Pat Corkery, NREL 17721. NREL prints on paper that contains...

Note: This page contains sample records for the topic "frequency variable voltage" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


221

Conserving Energy in Blast Freezers Using Variable Frequency Drives  

E-Print Network (OSTI)

; Freezing Time vs Velocity 6 7 8 9 10 11 12 13 14 0 500 1000 1500 Air Velocity (fpm) Freezing Time (hr) Freezing Time vs Carton Thickness 6 7 8 9 10 11 12 13 14 2 2.5 3 3.5 4 4.5 Carton Thickness (in.) Freezing Time (hr...: - Low-stage: 14? Hg vacuum (-50°F); - Intermediate stage controlled to 14 psig ( -2.5°F) and fluctuating some with load (increasing with higher load); - High-stage operates between 157 and 167 psig (87° and 91°F). An automatic monitoring...

Kolbe, E.; Ling, Q.; Wheeler, G.

2004-01-01T23:59:59.000Z

222

Sacramento Area Voltage Support Environmental Impact Statement  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

E E R R A N E V A D A R E G I O N Sacramento Area Voltage Support DRAFT ENVIRONMENTAL IMPACT STATEMENT DRAFT ENVIRONMENTAL IMPACT STATEMENT DOE/EIS-0323 NOVEMBER 2002 COVER SHEET Title: Sacramento Area Voltage Support Draft Environmental Impact Statement (EIS) Lead Agency: Western Area Power Administration (Western) Location: Alameda, Contra Costa, Placer, Sacramento, San Joaquin, and Sutter Counties, State of California. EIS Number: DOE/EIS-0323 Contact: Ms. Loreen McMahon, Environmental Project Manager Western Area Power Administration Sierra Nevada Region 114 Parkshore Drive Folsom, CA 95630 (916) 353-4460 (916) 985-1936 fax email: mcmahon@wapa.gov Website: Information is also available on our website: www.wapa.gov Hotline: 1-877-913-4440 (toll-free) Abstract The Western Area Power Administration's Central Valley Project transmission system forms an integral part of

223

High voltage electric substation performance in earthquakes  

SciTech Connect

This paper examines the performance of several types of high voltage substation equipment in past earthquakes. Damage data is provided in chart form. This data is then developed into a tool for estimating the performance of a substation subjected to an earthquake. First, suggests are made about the development of equipment class fragility curves that represent the expected earthquake performance of different voltages and types of equipment. Second, suggestions are made about how damage to individual pieces of equipment at a substation likely affects the post-earthquake performance of the substation as a whole. Finally, estimates are provided as to how quickly a substation, at various levels of damage, can be restored to operational service after the earthquake.

Eidinger, J. [G and E Engineering Systems, Oakland, CA (United States); Ostrom, D. [Southern California Edison, Rosemead, CA (United States); Matsuda, E. [Pacific Gas and Electric, San Francisco, CA (United States)

1995-12-31T23:59:59.000Z

224

Superconducting Fault Current Limiter for Transmission Voltage  

Science Journals Connector (OSTI)

Within a collaboration of American Superconductor, Siemens, Nexans and Southern California Edison one electrical phase of a resistive superconducting fault current limiter for the 115 kV transmission voltage level has been designed and manufactured. The active part of the limiter consists of 63 bifilar coils made of 12 mm wide steel-stabilized YBCO conductor and is housed in a cryostat operated at 5 bar and 74 K. The first phase was completely assembled and successfully subjected to power switching tests and high voltage tests. The basic design of the system and the test results are reported. The work was funded in part by US-DOE under Contract Number DE-FC26-07NT43243.

Hans-Peter Kraemer; Wolfgang Schmidt; Hong Cai; Bruce Gamble; David Madura; Tim MacDonald; Joe McNamara; Walther Romanosky; Greg Snitchler; Nicolas Lallouet; Frank Schmidt; Syed Ahmed

2012-01-01T23:59:59.000Z

225

Electrical system architecture having high voltage bus  

DOE Patents (OSTI)

An electrical system architecture is disclosed. The architecture has a power source configured to generate a first power, and a first bus configured to receive the first power from the power source. The architecture also has a converter configured to receive the first power from the first bus and convert the first power to a second power, wherein a voltage of the second power is greater than a voltage of the first power, and a second bus configured to receive the second power from the converter. The architecture further has a power storage device configured to receive the second power from the second bus and deliver the second power to the second bus, a propulsion motor configured to receive the second power from the second bus, and an accessory motor configured to receive the second power from the second bus.

Hoff, Brian Douglas (East Peoria, IL); Akasam, Sivaprasad (Peoria, IL)

2011-03-22T23:59:59.000Z

226

Low Voltage White Phosphorescent OLED Achievements  

Energy.gov (U.S. Department of Energy (DOE))

Universal Display Corporation (UDC) and its research partners at Princeton University and the University of Southern California have succeeded in developing a white phosphorescent OLED (PHOLED™) that achieved a record efficiency of 20 lumens per watt. This achievement is the result of the team's collaborative efforts to increase the efficiency of PHOLED lighting by focusing on two critical factors: lowering the drive voltages and increasing the amount of light extracted.

227

Classification of Voltage Sags Based on MPCA Models  

Science Journals Connector (OSTI)

In this paper, we introduce a new framework for classification of short duration voltage reductions in the area of Power Quality Monitoring using Multiway Principal Component Analysis (MPCA). Firstly, we recast the sags occurred in High Voltage (HV) ...

Abbas Khosravi; Joaquim Melendez; Joan Colomer

2007-06-01T23:59:59.000Z

228

Low voltage amplifier architecture for high speed switched capacitor circuits  

E-Print Network (OSTI)

This work concentrates on circuit realization of high speed and low voltage switched capacitor circuits, with emphasis on the operational transconductance amplifier (OTA). An overview of switched capacitor circuits is given. Speed and voltage...

Shankar, Asit

2012-06-07T23:59:59.000Z

229

Electro-optic voltage sensor head  

DOE Patents (OSTI)

The invention is an electro-optic voltage sensor head designed for integration with existing types of high voltage transmission and distribution apparatus. The sensor head contains a transducer, which comprises a transducing material in which the Pockels electro-optic effect is observed. In the practice of the invention at least one beam of electromagnetic radiation is routed into the transducing material of the transducer in the sensor head. The beam undergoes an electro-optic effect in the sensor head when the transducing material is subjected to an E-field. The electro-optic effect is observed as a differential phase a shift, also called differential phase modulation, of the beam components in orthogonal planes of the electromagnetic radiation. In the preferred embodiment the beam is routed through the transducer along an initial axis and then reflected by a retro-reflector back substantially parallel to the initial axis, making a double pass through the transducer for increased measurement sensitivity. The preferred embodiment of the sensor head also includes a polarization state rotator and at least one beam splitter for orienting the beam along major and minor axes and for splitting the beam components into two signals which are independent converse amplitude-modulated signals carrying E-field magnitude and hence voltage information from the sensor head by way of optic fibers.

Crawford, Thomas M. (Idaho Falls, ID); Davidson, James R. (Idaho Falls, ID); Woods, Gregory K. (Cornelius, OR)

1999-01-01T23:59:59.000Z

230

Coupling effects in inductive discharges with radio frequency substrate biasing  

SciTech Connect

Low pressure inductively coupled plasmas (ICP) operated in neon at 27.12 MHz with capacitive substrate biasing (CCP) at 13.56 MHz are investigated by phase resolved optical emission spectroscopy, voltage, and current measurements. Three coupling mechanisms are found potentially limiting the separate control of ion energy and flux: (i) Sheath heating due to the substrate biasing affects the electron dynamics even at high ratios of ICP to CCP power. At fixed CCP power, (ii) the substrate sheath voltage and (iii) the amplitude as well as frequency of plasma series resonance oscillations of the RF current are affected by the ICP power.

Schulze, J.; Schuengel, E.; Czarnetzki, U.

2012-01-09T23:59:59.000Z

231

Analysis and design of an electronic voltage ratchet  

E-Print Network (OSTI)

and decay. Impulse voltages are produced through the discharging of 0, capacitor into a shaping network consisting of resistors and a. capacitor as is shown in Figure 2. 9. The operation of the impulse generator is as follows. Capacitor Ci is charged from... voltage shaping network. as possible in order to reduce oscillations in the wavefront and wavetail portions of the impulse voltage [1). The impulse voltage generator requires a, highly charged capacitor or bank of capacitors. Capacitors may be charged...

Menendez, Jorge Carlos

2012-06-07T23:59:59.000Z

232

Low voltage vertical recording preamplifier for hard disk drives  

E-Print Network (OSTI)

. . . . . . . . . . . . . . . . . 4 2 Input drivers of the preamplifier along with the decoupling caps and parasitics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 3 Voltage bias voltage sensing scheme . . . . . . . . . . . . . . . . . . . 8 4 Current bias current... sensing scheme . . . . . . . . . . . . . . . . . . 9 5 Current bias scheme which common mode sense voltage to DE . . . . 10 6 Decoupling the inputs of the differential pair using feedback . . . . . 11 7 Barkhausen noise...

Mellachervu, Ramachandra Murthy

2004-11-15T23:59:59.000Z

233

Eastern Frequency Response Study  

SciTech Connect

This study was specifically designed to investigate the frequency response of the Eastern Interconnection that results from large loss-of-generation events of the type targeted by the North American Electric Reliability Corp. Standard BAL-003 Frequency Response and Frequency Bias Setting (NERC 2012a), under possible future system conditions with high levels of wind generation.

Miller, N.W.; Shao, M.; Pajic, S.; D'Aquila, R.

2013-05-01T23:59:59.000Z

234

Frequency selective infrared sensors  

DOE Patents (OSTI)

A frequency selective infrared (IR) photodetector having a predetermined frequency band. The exemplary frequency selective photodetector includes: a dielectric IR absorber having a first surface and a second surface substantially parallel to the first surface; an electrode electrically coupled to the first surface of the dielectric IR absorber; and a frequency selective surface plasmonic (FSSP) structure formed on the second surface of the dielectric IR absorber. The FSSP structure is designed to selectively transmit radiation in the predetermined frequency band that is incident on the FSSP structure substantially independent of the angle of incidence of the incident radiation on the FSSP structure.

Davids, Paul; Peters, David W

2013-05-28T23:59:59.000Z

235

Frequency selective infrared sensors  

SciTech Connect

A frequency selective infrared (IR) photodetector having a predetermined frequency band. The exemplary frequency selective photodetector includes: a dielectric IR absorber having a first surface and a second surface substantially parallel to the first surface; an electrode electrically coupled to the first surface of the dielectric IR absorber; and a frequency selective surface plasmonic (FSSP) structure formed on the second surface of the dielectric IR absorber. The FSSP structure is designed to selectively transmit radiation in the predetermined frequency band that is incident on the FSSP structure substantially independent of the angle of incidence of the incident radiation on the FSSP structure.

Davids, Paul; Peters, David W

2014-11-25T23:59:59.000Z

236

Voltage-dependent calcium channels and currents in native neurons and other cells have been divided into high voltage  

E-Print Network (OSTI)

Voltage-dependent calcium channels and currents in native neurons and other cells have been divided than one subtype of channel. A new subfamily of voltage-dependent calcium channel á1 subunit genes. 1999), having four domains, each with a voltage sensor and a pore-forming P loop. However

Dolphin, Annette C.

237

Microwave coupling of frequency-locked Josephson junction arrays  

SciTech Connect

A high temperature superconducting YBa{sub 2}Cu{sub 3}O{sub y} array of five Josephson junctions designed with additional coupling lines has been developed to demonstrate the effects of frequency locking and impedance matching for applications such as oscillators, mixers, and detectors. The Josephson self-radiation power was directly detected by a superheterodyne receiver, and Shapiro steps were also measured. The Josephson self-radiation properties reveal good quality of phase locking and microwave coupling with external circuits. The maximum self-radiation power of our array is about 50 pW which is several ten times higher than that of a single Josephson junction, and its peak point exactly satisfies the Josephson current-voltage relation. The Shapiro-step measurements show that the behavior of current-voltage curve depends on the effective inductance of coupling lines which affects the total impedance of Josephson junction array and microwave coupling. The Josephson oscillation frequency was obtained up to about 880 GHz which is 73{percent} of the maximum available frequency calculated from the characteristic voltage of the Josephson junctions. Experimental results show that this type of Josephson junction array can improve the Josephson self-radiation power and increase the maximum detectable frequency. {copyright} {ital 1997 American Institute of Physics.}

Song, I.; Eom, Y.; Park, G. [Department of Physics, Sogang University, Seoul 100-611 (Korea)] [Department of Physics, Sogang University, Seoul 100-611 (Korea); Lee, E.; Park, S. [Electronic Materials Laboratory, Samsung Advanced Institute of Technology, Suwon (Korea)] [Electronic Materials Laboratory, Samsung Advanced Institute of Technology, Suwon (Korea)

1997-06-01T23:59:59.000Z

238

Scheduling Processor Voltage and Frequency in Server and Cluster Systems Ramakrishna Kotla,  

E-Print Network (OSTI)

farm and cluster sites consume large quantities of energy both to power and cool the machines in the site. At the same time, less power supply redundancy is offered and power companies and government it using additional, real-world applications. 1. Introduction System-level and processor power is now

Freeh, Vincent

239

Plug-and-play voltage and frequency control of islanded microgrids with meshed topology  

E-Print Network (OSTI)

decentralized control scheme for Islanded microGrids (ImGs) composed by the interconnection of Distributed microGrids (ImG) has received major attention. ImGs are self-sufficient micro grids composed of several

Ferrari-Trecate, Giancarlo

240

Voltage and frequency control of islanded microgrids: a plug-and-play approach  

E-Print Network (OSTI)

propose a new decentralized control scheme for Islanded microGrids (ImGs) composed by the interconnection. INTRODUCTION In recent years, research on Islanded microGrids (ImG) has received major attention. ImGs are self

Ferrari-Trecate, Giancarlo

Note: This page contains sample records for the topic "frequency variable voltage" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


241

Micro-grid operation of inverter based distributed generation with voltage and frequency dependent loads  

E-Print Network (OSTI)

Distribution systems are experiencing increasing penetration of distributed generation (DG). One attractive option is to use the available DG capacity during utility outages by forming planned micro-grids. Load sharing ...

Zeineldin, H. H.

242

Off-chip Latency-Driven Dynamic Voltage and Frequency Scaling for an MPEG Decoding  

E-Print Network (OSTI)

. This workload decomposition is performed using a performance-monitoring unit (PMU) in the XScale-processor, which provides various statistics such as cache hit/miss and CPU stall, due to data dependency at run

Pedram, Massoud

243

Off-chip Latency-Driven Dynamic Voltage and Frequency Scaling for  

E-Print Network (OSTI)

-chip and off-chip components " Dynamic profiling data provided by embedded performance monitor unit on the CPU;5 Performance Monitoring Unit (PMU)Performance Monitoring Unit (PMU) ! PMU on the XScale can provide values memory access " no. of instructions being executed " branch mis-prediction " data stall ! Any two events

Pedram, Massoud

244

Dynamic Voltage and Frequency Scaling Under a Precise Energy Model Considering  

E-Print Network (OSTI)

is accessed Performance monitoring unit (PMU) ! Won is modeled as: ! PMU on the PXA255 processor chip can ! For DVFS, we use the PMU to generate statistics for " Total no. of instructions being executed (INSTR) " No. of stall cycles due to on/off-chip data dependencies (STALL) " No. of Data Cache misses (DMISS) ! We also

Pedram, Massoud

245

Capacitively coupled RF voltage probe having optimized flux linkage  

DOE Patents (OSTI)

An RF sensor having a novel current sensing probe and a voltage sensing probe to measure voltage and current. The current sensor is disposed in a transmission line to link all of the flux generated by the flowing current in order to obtain an accurate measurement. The voltage sensor is a flat plate which operates as a capacitive plate to sense voltage on a center conductor of the transmission line, in which the measured voltage is obtained across a resistance leg of a R-C differentiator circuit formed by the characteristic impedance of a connecting transmission line and a capacitance of the plate, which is positioned proximal to the center conductor.

Moore, James A. (Powell, TN); Sparks, Dennis O. (Maryville, TN)

1999-02-02T23:59:59.000Z

246

Method of Controlling Corona Effects and Breakdown Voltage of Small Air Gaps Stressed by Impulse Voltages  

E-Print Network (OSTI)

This paper investigates the influence of a resistor on the dielectric behavior of an air gap. The resistor is connected in series with the air gap and the latter is stressed by impulse voltage. Air gap arrangements of different geometry with either the rod or the plate grounded are stressed with impulse voltages of both positive and negative polarity. The resistor is connected in series with the air gap in the return circuit connecting the gap with the impulse generator. The method followed involves the investigation of the graphs of the charging time concerning the air gaps capacitances, in connection to the value of the resistor, the geometry of the gap, the effect of grounding and the polarity effect. It is determined that the charging time of the air gap increases, as the value of the resistor increases. It is also determined that the peak voltage value of the fully charged air gap decreases as the value of the resistor increases. The results of the mathematical and simulation analysis are compared with the results of the oscillograms taken from experimental work. In addition and consequently to the above results it is concluded from the experimental work that the in series connection of the resistor in the circuit has significant influence on corona pulses (partial discharges) occurring in the gap and on the breakdown voltage of the gap. A new method of controlling the corona effects and consequently the breakdown voltage of small air gaps stressed by impulse voltage of short duration in connection to the ground effect and the polarity effect has arisen. Furthermore through mathematical analysis of the charging graphs obtained from simulation and experimental oscillograms there was a calculation of the values of the capacitance of the air gaps in relation to their geometry and the results were compared to the values calculated with mathematical analysis.

Athanasios Maglaras; Trifon Kousiouris; Frangiskos Topalis; Dimitrios Katsaros; Leandros A. Maglaras; Konstantina Giannakopoulou

2014-10-15T23:59:59.000Z

247

Digital Control of Resonant Converters: Enhancing Frequency Resolution by Dithering  

E-Print Network (OSTI)

-resolution frequency drive when the quality factor of the network is high or to avoid limit cycle oscillations resolution enhancer for resonant network drive. I. INTRODUCTION In a variety of applications, variable ballasts piezoelectric devices) [1-3]. In such cases, the frequency resolution of the drive is crucial

248

Transient recovery voltage considerations in the application of medium voltage circuit breakers  

SciTech Connect

Medium Voltage Circuit Breakers can fail to interrupt 3-phase fault currents when power systems have Transient Recovery Voltage (TRV) characteristics which exceed the rating of the circuit breaker. This paper examines the application of 13.8kV generation and load switchgear for an oil refinery in which circuit parameters as originally designed would have exceeded the 13.8kV circuit breakers TRV ratings had corrective measures not been taken. This paper illustrates this case and discusses the basis of TRV, how TRV is assessed, and alternative actions taken to bring circuits to within the 13.8 kV circuit breaker ratings.

Swindler, D.L.; Schwartz, P.; Hamer, P.S.; Lambert, S.R.

1995-12-31T23:59:59.000Z

249

Kirchhoff voltage law corrected for radiating circuits  

E-Print Network (OSTI)

When a circular loop composed by a RLC is put to oscillate, the oscillation will eventually vanish in an exponentially decaying current, even considering superconducting wires, due to the emission of electric and magnetic dipole radiation. In this work we propose a modification on the Kirchhoff voltage law by adding the radiative contributions to the energy loss as an effective resistance, whose value is relatively small when compared to typical resistance value, but fundamental to describe correctly real circuits. We have also analysed the change in the pattern of the radiation spectra emitted by the circuit as we vary both the effective and electrical resistance.

Lara, Vitor

2014-01-01T23:59:59.000Z

250

A High Voltage Direct Current Generator  

Science Journals Connector (OSTI)

When powdered materials are blown through metal tubes by means of compressed air considerable quantities of electricity are produced by contact electrification. It was found that 6×10-5 coulombs could be produced per gram of diatomaceous earth, a form of silica, blown through a short length of copper tube. A generator of extremely high voltage is proposed, and a small scale model of such a generator is described, by means of which currents of 8×10-5 amperes at 260 kilovolts were generated.

Richard E. Vollrath

1932-10-15T23:59:59.000Z

251

High Frequency Effects of Variable Frequency Drives (VFD) on Electrical Submersible Pump (ESP) Systems  

E-Print Network (OSTI)

................................................................................................ 71 Table 10: Case III-B Result .............................................................................................. 72 Table 11: Case IV-A Result...

Ozkentli, Esra

2012-10-19T23:59:59.000Z

252

Safe epoxy encapsulant for high voltage magnetics  

SciTech Connect

This paper describes the use of Formula 456, an aliphatic amine cured epoxy for impregnating coils and high voltage transformers. Sandia has evaluated a number of MDA-free epoxy encapsulants which relied on either anhydride or other aromatic amine curing agents. The use of aliphatic amine curing agents was more recently evaluated and has resulted in the definition of Formula 456 resin. Methylene dianiline (MDA) has been used for more than 20 years as the curing agent for various epoxy formulations throughout the Department of Energy and much of industry. Sandia National Laboratories began the process of replacing MDA with other formulations because of regulations imposed by OSHA on the use of MDA. OSHA has regulated MDA because it is a suspect carcinogen. Typically the elimination of OSHA-regulated materials provides a rare opportunity to qualify new formulations in a range of demanding applications. It was important to take full advantage of that opportunity, although the associated materials qualification effort was costly. Small high voltage transformers are one of those demanding applications. The successful implementation of the new formulation for high reliability transformers will be described. The test results that demonstrate the parts are qualified for use in DOE weapon systems will be presented.

Sanchez, R.O.; Archer, W.E.

1998-01-01T23:59:59.000Z

253

Accelerator System Development at High Voltage Engineering  

SciTech Connect

Throughout the years, HVE has continuously extended the capabilities of its accelerator systems to meet the rising demands from a diverse field of applications, among which are deep level ion implantation, micro-machining, neutron production for biomedical research, isotope production or accelerator mass spectrometry. Characteristic for HVE accelerators is the coaxial construction of the all solid state power supply around the acceleration tubes. With the use of solid state technology, the accelerators feature high stability and very low ripple. Terminal voltages range from 1 to 6 MV for HVE Singletrons and Tandetrons. The high-current versions of these accelerators can provide ion beams with powers of several kW. In the last years, several systems have been built with terminal voltages of 1.25 MV, 2 MV and 5 MV. Recently, the first system based on a 6 MV Tandetron has passed the factory tests. In this paper we describe the characteristics of the HVE accelerator systems and present as example recent systems.

Klein, M. G.; Gottdang, A.; Haitsma, R. G.; Mous, D. J. W. [High Voltage Engineering Europa B.V., P.O. Box 99, Amersfoort 3800 AB (Netherlands)

2009-03-10T23:59:59.000Z

254

Low voltage operation of plasma focus  

Science Journals Connector (OSTI)

Plasma foci of compact sizes and operating with low energies (from tens of joules to few hundred joules) have found application in recent years and have attracted plasma-physics scientists and engineers for research in this direction. We are presenting a low energy and miniature plasma focus which operates from a capacitor bank of 8.4 ? ? F capacity charged at 4.2–4.3 kV and delivering approximately 52 kA peak current at approximately 60 nH calculated circuit inductance. The total circuit inductance includes the plasma focusinductance. The reported plasma focus operates at the lowest voltage among all reported plasma foci so far. Moreover the cost of capacitor bank used for plasma focus is nearly 20 U.S. dollars making it very cheap. At low voltage operation of plasma focus the initial breakdown mechanism becomes important for operation of plasma focus. The quartz glass tube is used as insulator and breakdown initiation is done on its surface. The total energy of the plasma focus is approximately 75 J. The plasma focus system is made compact and the switching of capacitor bank energy is done by manual operating switch. The focus is operated with hydrogen and deuterium filled at 1–2 mbar.

Rohit Shukla; S. K. Sharma; P. Banerjee; R. Das; P. Deb; T. Prabahar; B. K. Das; B. Adhikary; A. Shyam

2010-01-01T23:59:59.000Z

255

E-Print Network 3.0 - acute vocal variability Sample Search Results  

NLE Websites -- All DOE Office Websites (Extended Search)

phonation Patrick Mergella) Summary: upon variation in some other variable, such as frequency or the angle of the vocal membranes... Modeling the role of nonhuman vocal membranes...

256

Changes in hydrological extremes and climate variability in the Severn Uplands.  

E-Print Network (OSTI)

??Hydrological extremes within the UK have increased in intensity, frequency and persistence over recent years and are predicted to increase in variability throughout the 21st… (more)

Biggs, Eloise M.

2009-01-01T23:59:59.000Z

257

Frequency Combs for Astronomy  

Science Journals Connector (OSTI)

For the first time a mode filtered frequency comb has been used to calibrate an astronomical spectrometer online. Solar and calibration spectra have been recorded simultaneously.

Wilken, Tobias; Hänsch, Theodor W; Udem, Thomas; Steinmetz, Tilo; Holzwarth, Ronald; Araujo-Hauck, Constanza; Pasquini, Luca; D'Odorico, Sandro; Manescau, Antonio; Murphy, Michael T; Kentischer, Thomas; Schmidt, Wolfgang

258

Method for sputtering with low frequency alternating current  

DOE Patents (OSTI)

Low frequency alternating current sputtering is provided by connecting a low frequency alternating current source to a high voltage transformer having outer taps and a center tap for stepping up the voltage of the alternating current. The center tap of the transformer is connected to a vacuum vessel containing argon or helium gas. Target electrodes, in close proximity to each other, and containing material with which the substrates will be coated, are connected to the outer taps of the transformer. With an applied potential, the gas will ionize and sputtering from the target electrodes onto the substrate will then result. The target electrodes can be copper or boron, and the substrate can be stainless steel, aluminum, or titanium. Copper coatings produced are used in place of nickel and/or copper striking. 6 figs.

Timberlake, J.R.

1996-04-30T23:59:59.000Z

259

Method for sputtering with low frequency alternating current  

DOE Patents (OSTI)

Low frequency alternating current sputtering is provided by connecting a low frequency alternating current source to a high voltage transformer having outer taps and a center tap for stepping up the voltage of the alternating current. The center tap of the transformer is connected to a vacuum vessel containing argon or helium gas. Target electrodes, in close proximity to each other, and containing material with which the substrates will be coated, are connected to the outer taps of the transformer. With an applied potential, the gas will ionize and sputtering from the target electrodes onto the substrate will then result. The target electrodes can be copper or boron, and the substrate can be stainless steel, aluminum, or titanium. Copper coatings produced are used in place of nickel and/or copper striking.

Timberlake, John R. (Allentown, NJ)

1996-01-01T23:59:59.000Z

260

Discrete and Continuous Min-Energy Schedules for Variable Voltage Processors  

E-Print Network (OSTI)

. A theoretical model for min-energy job scheduling was first proposed a decade ago, and it was shown that for any convex energy function, the min-energy schedule for a set of n jobs has a unique characterization/speed), it saves energy to execute jobs as slowly as possible while still satisfying all timing constraints

Li, Minming

Note: This page contains sample records for the topic "frequency variable voltage" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


261

Stabilized radio frequency quadrupole  

DOE Patents (OSTI)

Disclosed is a long-vane stabilized radio frequency resonator for accelerating charged particles and including means defining a radio frequency resonator cavity, a plurality of long vanes mounted in the defining means for dividing the cavity into sections, and means interconnecting opposing ones of the plurality of vanes for stabilizing the resonator. 5 figs.

Lancaster, H.D.; Fugitt, J.A.; Howard, D.R.

1984-12-25T23:59:59.000Z

262

Standard Frequency Broadcasts  

Science Journals Connector (OSTI)

... Mc./sec., at least three of which are available at any time; standard audio frequencies of 440 and 4,000 c./sec. broadcast on these carriers; and ... second of every minute the pulse is omitted. The 1-min. interval in the audio-frequency transmission is used to give the station announcement, either in Morse or (at ...

1944-09-02T23:59:59.000Z

263

Definition: Frequency-Domain Electromagnetics Survey | Open Energy  

Open Energy Info (EERE)

Frequency-Domain Electromagnetics Survey Frequency-Domain Electromagnetics Survey Jump to: navigation, search Dictionary.png Frequency-Domain Electromagnetics Survey Frequency-domain electromagnetic techniques are continuous wave field methods which enable the mapping of the electrical conductivity of the subsurface through electromagnetic induction.[1] View on Wikipedia Wikipedia Definition Electromagnetic induction is the production of a potential difference (voltage) across a conductor when it is exposed to a varying magnetic field. Michael Faraday is generally credited with the discovery of induction in 1831 though it may have been anticipated by the work of Francesco Zantedeschi in 1829. Around 1830 to 1832, Joseph Henry made a similar discovery, but did not publish his findings until later. Faraday's

264

Dynamic frequency tuning of electric and magnetic metamaterial response  

DOE Patents (OSTI)

A geometrically modifiable resonator is comprised of a resonator disposed on a substrate, and a means for geometrically modifying the resonator. The geometrically modifiable resonator can achieve active optical and/or electronic control of the frequency response in metamaterials and/or frequency selective surfaces, potentially with sub-picosecond response times. Additionally, the methods taught here can be applied to discrete geometrically modifiable circuit components such as inductors and capacitors. Principally, controlled conductivity regions, using either reversible photodoping or voltage induced depletion activation, are used to modify the geometries of circuit components, thus allowing frequency tuning of resonators without otherwise affecting the bulk substrate electrical properties. The concept is valid over any frequency range in which metamaterials are designed to operate.

O'Hara, John F; Averitt, Richard; Padilla, Willie; Chen, Hou-Tong

2014-09-16T23:59:59.000Z

265

High Temperature, High Voltage Fully Integrated Gate Driver Circuit  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

driver circuit, 5-V on- chip voltage regulator, short-circuit protection, undervoltage lockout, bootstrap capacitor, dead time controller and temperature sensor * 0.8-micron,...

266

Triple voltage dc-to-dc converter and method  

DOE Patents (OSTI)

A circuit and method of providing three dc voltage buses and transforming power between a low voltage dc converter and a high voltage dc converter, by coupling a primary dc power circuit and a secondary dc power circuit through an isolation transformer; providing the gating signals to power semiconductor switches in the primary and secondary circuits to control power flow between the primary and secondary circuits and by controlling a phase shift between the primary voltage and the secondary voltage. The primary dc power circuit and the secondary dc power circuit each further comprising at least two tank capacitances arranged in series as a tank leg, at least two resonant switching devices arranged in series with each other and arranged in parallel with the tank leg, and at least one voltage source arranged in parallel with the tank leg and the resonant switching devices, said resonant switching devices including power semiconductor switches that are operated by gating signals. Additional embodiments having a center-tapped battery on the low voltage side and a plurality of modules on both the low voltage side and the high voltage side are also disclosed for the purpose of reducing ripple current and for reducing the size of the components.

Su, Gui-Jia (Knoxville, TN)

2008-08-05T23:59:59.000Z

267

fault diagnosis of a high voltage transmission line using waveform ...  

E-Print Network (OSTI)

Oct 4, 2013 ... FAULT DIAGNOSIS OF A HIGH VOLTAGE TRANSMISSION LINE USING ... Fault types such as single line to ground, line to line, double line to ...

Ripunjoy Phukan

2013-10-04T23:59:59.000Z

268

Capability constraints to mitigate voltage fluctuations from DFIG wind farms when delivering ancillary services to the network  

Science Journals Connector (OSTI)

Abstract Majority of the wind power resources are typically sited at remote locations in power networks and generated power is transmitted through rural transmission corridors to load centres. With increased penetration level of the wind generation there is an increased requirement to provide ancillary services from distributed wind power resources, hence they are operated under different control strategies to provide ancillary services to the network. The control strategies and capability characteristics will significant impact on voltage fluctuations in distribution networks. This paper presents a comparative analysis between different wind generator control strategies (i.e. power factor control strategy, voltage control strategy and reactive power dispatch strategy) on network voltage fluctuations during variable wind conditions while considering extended reactive power capability (i.e. with both generator and power electronic converter reactive power capabilities) for the doubly-fed induction generator (DFIG). Voltage fluctuations are analysed using real wind data measured at a DFIG based wind farm, and the wind farm model was verified against real measurements. Study has shown that voltage fluctuations are exacerbated when wind generator is at mode transition (i.e. from power optimisation mode to power limitation mode). A sensitivity analysis has shown that voltage fluctuations are exacerbated due to the limitations of the reactive power capability of the DFIG, and the operating point of the DFIG power curve irrespective of the control strategy implemented at the wind generator. Furthermore, a mitigation strategy was developed as an integrated control scheme to the main control scheme in order to reduce voltage fluctuations due to wind power variations. However, effectiveness of the mitigation strategy is greatly affected by the reactive power capability of the DFIG, in particular during high wind turbulences.

Lasantha Meegahapola; Sarath Perera

2014-01-01T23:59:59.000Z

269

Backstepping control of DFIG generators for wide-range variable-speed wind turbines  

Science Journals Connector (OSTI)

In this paper, we have presented a general study of self excited induction generator used in isolated renewable energy conversion source. Tthe behaviour of generated voltage under variable load, rotor speed and excitation capacitance is presented. Also, we have proposed a robust controller suitable in order to control the terminal DC voltage under different speed and AC load conditions for supplied an isolated DC load. The experimental characteristic curve of the generator and simulation result of proposed control scheme are presented.

Badre Bossoufi; Mohammed Karim; Ahmed Lagrioui; Mohammed Taoussi; Mohamed Larbi ElHafyani

2014-01-01T23:59:59.000Z

270

Low voltage ride-through capability improvement of DFIG-based wind turbines under unbalanced voltage dips  

Science Journals Connector (OSTI)

Abstract This paper proposes a competent and effective scheme to enhance the ride-through capability of DFIG-based wind turbines under unbalanced voltage dip conditions. The proposed method is realized through joint use of the rotor-side converter control and a three-phase stator damping resistor (SDR) placed in series with the stator windings. By means of an asymmetrical SDR idea, during the unbalanced voltage dip the SDR resistors are activated only in phase(s) experiencing low voltage. Then, the rotor current is controlled such that no unbalance voltage appears on the stator voltage. The proposed ride-through approach limits the peak values of the rotor inrush current, electromagnetic torque and DFIG transient response at the times of occurrence and clearing the fault. It also suppresses fluctuation of the electromagnetic torque and DFIG transient response appeared during unbalanced voltage dips due to negative sequence component.

Mohsen Rahimi; Mostafa Parniani

2014-01-01T23:59:59.000Z

271

Qualification High Voltage Testing of Short Triax HTS Cables in the Laboratory  

SciTech Connect

In order to qualify the electrical insulation design of future HTS cables installed in the electric grid, a number of high voltage qualification tests are generally performed in the laboratory on either single-phase model cables and/or actual three-phase cable samples. Prior to installation of the 200-m Triax HTS cable at the American Electric Power Bixby substation near Columbus, Ohio, in September, 2006, such tests were conducted on both single-phase model cables made at ORNL and tri-axial cable sections cut off from cable made on a production run. The three-phase tri-axial design provides some specific testing challenges since the ground shield and three phases are concentric about a central former with each phase separated by dielectric tape insulation immersed in liquid nitrogen. The samples were successfully tested and qualified for partial discharge inception, AC withstand, and lightning impulse where voltage is applied to one phase with the other phases grounded. In addition one of the phase pairs was tested for dc withstand as a ldquoworst caserdquo scenario to simulate the effect of VLF (Very Low Frequency) tests on the actual cable installed at the Bixby site. The model and prototype cables will be described and the high voltage test results summarized.

James, David Randy [ORNL; Sauers, Isidor [ORNL; Ellis, Alvin R [ORNL; Tuncer, Enis [ORNL; Gouge, Michael J [ORNL; Demko, Jonathan A [ORNL; Duckworth, Robert C [ORNL; Rey, Christopher M [ORNL

2009-01-01T23:59:59.000Z

272

Low voltage ride-through of DFIG and brushless DFIG: Similarities and differences  

Science Journals Connector (OSTI)

Abstract The brushless doubly fed induction generator (BDFIG) has been proposed as a viable alternative in wind turbines to the commonly used doubly fed induction generator (DFIG). The BDFIG retains the benefits of the DFIG, i.e. variable speed operation with a partially rated converter, but without the use of brush gear and slip rings, thereby conferring enhanced reliability. As low voltage ride-through (LVRT) performance of the DFIG-based wind turbine is well understood, this paper aims to analyze LVRT behavior of the BDFIG-based wind turbine in a similar way. In order to achieve this goal, the equivalence between their two-axis model parameters is investigated. The variation of flux linkages, back-EMFs and currents of both types of generator are elaborated during three phase voltage dips. Moreover, the structural differences between the two generators, which lead to different equivalent parameters and hence different LVRT capabilities, are investigated. The analytical results are verified via time-domain simulations for medium size wind turbine generators as well as experimental results of a voltage dip on a prototype 250 kVA BDFIG.

S. Tohidi; P. Tavner; R. McMahon; H. Oraee; M.R. Zolghadri; S. Shao; E. Abdi

2014-01-01T23:59:59.000Z

273

Graphene Frequency Multipliers  

E-Print Network (OSTI)

In this letter, the ambipolar transport properties of graphene flakes have been used to fabricate full-wave signal rectifiers and frequency-doubling devices. By correctly biasing an ambipolar graphene field-effect transistor ...

Wang, Han

274

Mechanically tunable plasma frequency  

E-Print Network (OSTI)

in S12 phases. function [eps, x] = FindPerm(Thru, Sample,It returns the permittivity (eps) and a frequency matrix %0; % Initialize results matrix eps = zeros(n,1); for i = 1:n

Schuil, Crystal Joy

2009-01-01T23:59:59.000Z

275

Simplified VO M&V Protocol Simplified Voltage Optimization (VO)  

E-Print Network (OSTI)

Simplified VO M&V Protocol 1 Simplified Voltage Optimization (VO) Measurement and Verification Protocol 1.0 Introduction 1.1 Purpose The Simplified Voltage Optimization (VO) Measurement and Verification requirements, and measurement and verification formulations are included as part of this Protocol. 1

276

Task Scheduling and Voltage Selection for Energy Minimization  

E-Print Network (OSTI)

system con gurations. 1. INTRODUCTION Energy consumption has become a primary concern in today's ICTask Scheduling and Voltage Selection for Energy Minimization Yumin Zhang Synopsys, Inc. 700 East-phase framework that inte- grates task assignment, ordering and voltage selection VS together to minimize energy

Hu, Xiaobo Sharon

277

IMPACT OF DYNAMIC VOLTAGE SCALING (DVS) ON CIRCUIT OPTIMIZATION  

E-Print Network (OSTI)

and dynamic power, respectively. Both gate sizing and Dual-VT are design-time techniques, which are applied to the circuit at a fixed voltage. On the other hand, DVS is a run-time technique and implies that the circuit will be operating at a different voltage...

Esquit Hernandez, Carlos A.

2010-01-16T23:59:59.000Z

278

REFINED RFP LOOP VOLTAGE CALCULATION J.C. Sprott  

E-Print Network (OSTI)

is the stored magnetic energy, Up is the plasma energy, and 'E is the global energy confinement time, which-of-merit for RFP devices is the loop voltage. Low loop voltage implies high plasma temperature and long energy is smallest if the loop is as close to the outside of the shell and as far from the primary windings

Sprott, Julien Clinton

279

LOW VOLTAGE ANALOG CIRCUITS USING STANDARD CMOS TECHNOLOGY  

E-Print Network (OSTI)

LOW VOLTAGE ANALOG CIRCUITS USING STANDARD CMOS TECHNOLOGY Phillip E. Allen, Benjamin J. Blalock, and Gabriel A. Rincon School of Electrical and Computer Engineering Georgia Institute of Technology Atlanta supply voltages in CMOS integrated circuits. As the channel lengths of CMOS technology decrease

Rincon-Mora, Gabriel A.

280

Measurement of high voltage using Rutherford backscattering spectrometry  

E-Print Network (OSTI)

A novel variation of Rutherford Backscattering Spectrometry (RBS) has been utilized to measure a high voltage collected on an aluminum target by Direct Energy Conversion. The maximum high voltage on the target was measured to be 97.5 kV +/- 2 kV...

Abrego, Celestino Pete

2007-04-25T23:59:59.000Z

Note: This page contains sample records for the topic "frequency variable voltage" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


281

Nonlinear voltages in multiple-lead coherent conductors  

Science Journals Connector (OSTI)

We use the generalized S-matrix approach to study multiple-lead coherent conductors in the case of finite applied voltages. In this framework we discuss the transverse voltage arising in a four-lead conductor with two symmetric biased leads.

Gordey B. Lesovik and Carlo Presilla

1993-01-15T23:59:59.000Z

282

The Cavendish high-voltage laboratory 1935–39  

Science Journals Connector (OSTI)

...the period covered. Nuclear Transmutation|Cavendish...development of high-voltage nuclear transmutation equipment...experimental work in nuclear physics though he continued...a new high-voltage accelerator therefore fell mainly...doubler circuit with six vacuum rectifiers forming a...

1999-01-01T23:59:59.000Z

283

Spark-safe low-voltage detonator  

DOE Patents (OSTI)

A column of explosive in a low-voltage detonator which makes it spark-safe ncludes an organic secondary explosive charge of HMX in the form of a thin pad disposed in a bore of a housing of the detonator in an ignition region of the explosive column and adjacent to an electrical ignition device at one end of the bore. The pad of secondary charge has an axial thickness within the range of twenty to thirty percent of its diameter. The explosive column also includes a first explosive charge of CP disposed in the housing bore in the ignition region of the explosive column next to the secondary charge pad on a side opposite from the ignition device. The first CP charge is loaded under sufficient pressure, 25 to 40 kpsi, to provide mechanical confinement of the pad of secondary charge and physical coupling thereof with the ignition device. The explosive column further includes a second explosive charge of CP disposed in the housing bore in a transition region of the explosive column next to the first CP charge on a side opposite from the pad of secondary charge. The second CP charge is loaded under sufficient pressure, about 10 kpsi, to allow occurrence of DDT. The first explosive CP charge has an axial thickness within the range of twenty to thirty percent of its diameter, whereas the second explosive CP charge contains a series of increments (nominally 4) each of which has an axial thickness-to-diameter ratio of one to two.

Lieberman, Morton L. (Albuquerque, NM)

1989-01-01T23:59:59.000Z

284

Bonfire-safe low-voltage detonator  

DOE Patents (OSTI)

A column of explosive in a low-voltage detonator which makes it bonfire-safe includes a first layer of an explosive charge of CP, or a primary explosive, and a second layer of a secondary organic explosive charge, such as PETN, which has a degradation temperature lower than the autoignition temperature of the CP or primary explosives. The first layer is composed of a pair of increments disposed in a bore of a housing of the detonator in an ignition region of the explosive column and adjacent to and in contact with an electrical ignition device at one end of the bore. The second layer is composed of a plurality of increments disposed in the housing bore in a transition region of the explosive column next to and in contact with the first layer on a side opposite from the ignition device. The first layer is loaded under a sufficient high pressure, 25 to 40 kpsi, to achieve ignition, whereas the second layer is loaded under a sufficient low pressure, about 10 kpsi, to allow occurrence of DDT. Each increment of the first and second layers has an axial length-to-diameter ratio of one-half.

Lieberman, Morton L. (Albuquerque, NM)

1990-01-01T23:59:59.000Z

285

IEEE POWER ELECTRONICS LETTERS 1 A Constant-Frequency Method for Improving  

E-Print Network (OSTI)

these are resonant gate drive [3]­[5], pulse frequency modulation (PFM) [6], and a hybrid Manuscript received, in the case of the variable-frequency methods, their potential for generating undesired noise at subharmonicsIEEE POWER ELECTRONICS LETTERS 1 A Constant-Frequency Method for Improving Light-Load Efficiency

Lee, Thomas H.

286

Definition: Automated Voltage And Var Control | Open Energy Information  

Open Energy Info (EERE)

Voltage And Var Control Voltage And Var Control Jump to: navigation, search Dictionary.png Automated Voltage And Var Control Automated voltage and VAR control requires coordinated operation of reactive power resources such as capacitor banks, voltage regulators, transformer load-tap changers, and distributed generation (DG) with sensors, controls, and communications systems. These devices could operate autonomously in response to local events or in response to signals from a central control system.[1] View on Wikipedia Wikipedia Definition Also Known As Volt-VAR Control (VVC) Related Terms smart grid, Reactive Power References ↑ SmartGrid.gov 'Description of Functions' An i LikeLike UnlikeLike You like this.Sign Up to see what your friends like. nline Glossary Definition Retrieved from

287

Living and Working Safely Around High-Voltage Power Lines.  

SciTech Connect

High-voltage transmission lines can be just as safe as the electrical wiring in the homes--or just as dangerous. The crucial factor is ourselves: they must learn to behave safely around them. This booklet is a basic safety guide for those who live and work around power lines. It deals primarily with nuisance shocks due to induced voltages, and with potential electric shock hazards from contact with high-voltage lines. References on possible long-term biological effects of transmission lines are shown. In preparing this booklet, the Bonneville Power Administration has drawn on more than 50 years of experience with high-voltage transmission. BPA operates one of the world`s largest networks of long-distance, high-voltage lines. This system has more than 400 substations and about 15,000 miles of transmission lines, almost 4,400 miles of which are operated at 500,000 volts.

United States. Bonneville Power Administration.

2001-06-01T23:59:59.000Z

288

AC Resonant charger with charge rate unrelated to primary power frequency  

DOE Patents (OSTI)

An AC resonant charger for a capacitive load, such as a PFN, is provided with a variable repetition rate unrelated to the frequency of a multi-phase AC power source by using a control unit to select and couple the phase of the power source to the resonant charger in order to charge the capacitive load with a phase that is the next to begin a half cycle. For optimum range in repetition rate and increased charging voltage, the resonant charger includes a step-up transformer and full-wave rectifier. The next phase selected may then be of either polarity, but is always selected to be of a polarity opposite the polarity of the last phase selected so that the transformer core does not saturate. Thyristors are used to select and couple the correct phase just after its zero crossover in response to a sharp pulse generated by a zero-crossover detector. The thyristor that is turned on then automatically turns off after a full half cycle of its associated phase input. A full-wave rectifier couples the secondary winding of the transformer to the load so that the load capacitance is always charged with the same polarity.

Watson, Harold (Torrance, CA)

1982-01-01T23:59:59.000Z

289

Monte Carlo method for estimating backflashover rates on high voltage transmission lines  

Science Journals Connector (OSTI)

Abstract This paper presents a novel Monte-Carlo based model for the analysis of backflashover rate (BFOR) on high voltage transmission lines. The proposed model aims to take into the account following aspects of the BFOR phenomenon: transmission line (TL) route keraunic level(s), statistical depiction of lightning-current parameters (including statistical correlation), electrogeometric model of lightning attachment, frequency-dependence of TL parameters and electromagnetic coupling effects, tower geometry and surge impedance, tower grounding impulse impedance (with soil ionization), lightning-surge reflections from adjacent towers, non-linearity of the insulator strings flashover characteristic, distribution of lightning strokes along the TL span and power frequency voltage. In the analysis of the BFOR, special attention is given to the influences emanating from the insulator strings flashover characteristic and lightning statistics. The model could be applied to the transmission line as a whole or some of its portions, e.g. first several towers emanating from the substation or several towers crossing a mountain ridge.

Petar Sarajcev

2015-01-01T23:59:59.000Z

290

Frequency Control Of Micro Hydro Power Plant Using Electronic Load Controller  

E-Print Network (OSTI)

Water turbines, like petrol or diesel engines, will vary in speed as load is applied or relieved. Although not such a great problem with machinery which uses direct shaft power, this speed variation will seriously affect both frequency and voltage output from a generator. Traditionally, complex hydraulic or mechanical speed governors altered flow as the load varied, but more recently an electronic load controller (ELC) has been developed which has increased the simplicity and reliability of modern micro-hydro sets. An ELC is a solid-state electronic device designed to regulate output power of a micro-hydropower system and maintaining a near-constant load on the turbine generates stable voltage and frequency. In this paper an ELC constantly senses and regulates the generated frequency. The frequency is directly proportional to the speed of the turbine.

unknown authors

291

A Radiofrequency High-Voltage Generator  

Science Journals Connector (OSTI)

A large radio oscillator with unrectified alternating anode power-supply sends high-frequency power into a 50 meter wave-length antenna which is coiled up without insulation, and enclosed in a metal vacuum tank. Over 800,000 volts is generated inside of the tank exactly where it is to be used for x-rays or for accelerating ions. There is no insulation to become punctured. Single tuned-circuit resonance transformers are superior to coupled tuned-circuit Tesla coils. Resonance transformers, oscillator circuits, power tubes, power supply and coil construction are described. X-ray production, and ion acceleration are outlined.

David H. Sloan

1935-01-01T23:59:59.000Z

292

Frequency stability considerations in the design of battery-powered VHF transmitters  

E-Print Network (OSTI)

Klughart, S, B. , Massachusetts Institute of Technology Chair of Advisory Committee: Dr. Edgar Sanchez-Sinencio Traditional VHF transmitter oscillators operating in the 50-100 MHz frequency range have as their power source a regulated power supply with a..., the variation in pawer supply voltage and non-zero battery supply source resistance are of greater impact on oscillator frequency stability than temperature variations. The major mechanisms which contribute to this &equency drift are due to changes in active...

Klughart, Kevin Mark

1992-01-01T23:59:59.000Z

293

Electro-optic voltage sensor with Multiple Beam Splitting  

DOE Patents (OSTI)

A miniature electro-optic voltage sensor system capable of accurate operation at high voltages without use of the dedicated voltage dividing hardware. The invention achieves voltage measurement without significant error contributions from neighboring conductors or environmental perturbations. The invention employs a transmitter, a sensor, a detector, and a signal processor. The transmitter produces a beam of electromagnetic radiation which is routed into the sensor. Within the sensor the beam undergoes the Pockels electro-optic effect. The electro-optic effect produces a modulation of the beam's polarization, which is in turn converted to a pair of independent conversely-amplitude-modulated signals, from which the voltage of the E-field is determined by the signal processor. The use of converse AM signals enables the signal processor to better distinguish signal from noise. The sensor converts the beam by splitting the beam in accordance with the axes of the beam's polarization state (an ellipse) into at least two AM signals. These AM signals are fed into a signal processor and processed to determine the voltage between a ground conductor and the conductor on which voltage is being measured.

Woods, Gregory K. (Cornelius, OR); Renak, Todd W. (Idaho Falls, ID); Crawford, Thomas M. (Idaho Falls, ID); Davidson, James R. (Idaho Falls, ID)

2000-01-01T23:59:59.000Z

294

Electro-optic voltage sensor with beam splitting  

DOE Patents (OSTI)

The invention is a miniature electro-optic voltage sensor system capable of accurate operation at high voltages without use of the dedicated voltage dividing hardware typically found in the prior art. The invention achieves voltage measurement without significant error contributions from neighboring conductors or environmental perturbations. The invention employs a transmitter, a sensor, a detector, and a signal processor. The transmitter produces a beam of electromagnetic radiation which is routed into the sensor. Within the sensor the beam undergoes the Pockels electro-optic effect. The electro-optic effect produces a modulation of the beam's polarization, which is in turn converted to a pair of independent conversely-amplitude-modulated signals, from which the voltage of the E-field is determined by the signal processor. The use of converse AM signals enables the signal processor to better distinguish signal from noise. The sensor converts the beam by splitting the beam in accordance with the axes of the beam's polarization state (an ellipse) into at least two AM signals. These AM signals are fed into a signal processor and processed to determine the voltage between a ground conductor and the conductor on which voltage is being measured.

Woods, Gregory K. (Cornelius, OR); Renak, Todd W. (Idaho Falls, ID); Davidson, James R. (Idaho Falls, ID); Crawford, Thomas M. (Idaho Falls, ID)

2002-01-01T23:59:59.000Z

295

Panel Session: Optimization Techniques in Voltage Collapse Analysis," IEEE PES Summer Meeting, San Diego, July 14, 1998. Applications of Optimization to Voltage Collapse Analysis  

E-Print Network (OSTI)

Panel Session: Optimization Techniques in Voltage Collapse Analysis," IEEE PES Summer Meeting, San Diego, July 14, 1998. Applications of Optimization to Voltage Collapse Analysis Claudio A. Ca|Thispaper describesseveralapplica- tions of optimization for voltage stability analysis VSA of power systems. Voltage stability prob

Cañizares, Claudio A.

296

Nonequilibrium atmospheric pressure plasma jet using a combination of 50?kHz/2?MHz dual-frequency power sources  

Science Journals Connector (OSTI)

An atmospheric pressure plasma jet is generated by dual sinusoidal wave (50?kHz and 2?MHz). The dual-frequency plasma jet exhibits the advantages of both low frequency and radio frequency plasmas namely the long plasma plume and the high electron density. The radio frequency ignition voltage can be reduced significantly by using dual-frequency excitation compared to the conventional radio frequency without the aid of the low frequency excitation source. A larger operating range of ? mode discharge can be obtained using dual-frequency excitation which is important to obtain homogeneous and low-temperature plasma. A larger controllable range of the gas temperature of atmospheric pressure plasma could also be obtained using dual-frequency excitation.

Yong-Jie Zhou; Qiang-Hua Yuan; Fei Li; Xiao-Min Wang; Gui-Qin Yin; Chen-Zhong Dong

2013-01-01T23:59:59.000Z

297

Optically triggered high voltage switch network and method for switching a high voltage  

DOE Patents (OSTI)

An optically triggered solid state switch and method for switching a high voltage electrical current. A plurality of solid state switches (350) are connected in series for controlling electrical current flow between a compensation capacitor (112) and ground in a reactive power compensator (50, 50') that monitors the voltage and current flowing through each of three distribution lines (52a, 52b and 52c), which are supplying three-phase power to one or more inductive loads. An optical transmitter (100) controlled by the reactive power compensation system produces light pulses that are conveyed over optical fibers (102) to a switch driver (110') that includes a plurality of series connected optical triger circuits (288). Each of the optical trigger circuits controls a pair of the solid state switches and includes a plurality of series connected resistors (294, 326, 330, and 334) that equalize or balance the potential across the plurality of trigger circuits. The trigger circuits are connected to one of the distribution lines through a trigger capacitor (340). In each switch driver, the light signals activate a phototransistor (300) so that an electrical current flows from one of the energy reservoir capacitors through a pulse transformer (306) in the trigger circuit, producing gate signals that turn on the pair of serially connected solid state switches (350).

El-Sharkawi, Mohamed A. (Renton, WA); Andexler, George (Everett, WA); Silberkleit, Lee I. (Mountlake Terrace, WA)

1993-01-19T23:59:59.000Z

298

High-voltage supply for backward-wave tube  

SciTech Connect

A high-current high-voltage supply for a backward-wave tube is described that uses a generalppurpose semiconductor converter with pulse-width modulation and two-stage regulation. The load current is up to 250 mA for load voltages of from 0.5 to 4.5 kV. The voltage staiblity is less than or equal to 5 x 10/sup -6/. the root-mean-square output ripple is less than or equal to 2 x 10/sup -6// The supply is equipped with high-speed (5 usec) load-breakdown protection.

Bryvkhanov, A.N.; Kosarev, P.M.; Latushkin, S.T.; Yudin, L.I.

1986-04-01T23:59:59.000Z

299

Frequencies for Radio Astronomy  

Science Journals Connector (OSTI)

... must therefore be achieved through the combined action of three international scientific unions, IAU (astronomy), COSPAR (space) and URSI (radio), which jointly delegate members to an ... jointly delegate members to an Inter-Union Commission for the Allocation of Frequencies for Radio Astronomy and Space Science (IUCAF). This Commission discusses the scientific case for protecting various ...

F. G. SMITH

1970-10-31T23:59:59.000Z

300

Research to Prevent the Anti-charging Incident of the Voltage Transformer in the Substation  

Science Journals Connector (OSTI)

The voltage transformer of the power system is a device which converts the high voltage of the primary side into the low voltage required by secondary device, and the primary side connects to the primary syste...

Hui-Ying Chen; Zhi-Peng Wang; Mu-Qin Tian

2011-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "frequency variable voltage" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


301

A 1.6-to-3.2/4.8 GHz Dual-Modulus Injection-Locked Frequency Multiplier in 0.18  

E-Print Network (OSTI)

: hwu@ece.rochester.edu Abstract-- This paper proposes a variable-modulus injection- locked frequency. Variable-modulus frequency multiplier can be a low-cost solution for a multi-band system to switch, as the frequency multiplier needs to drive its load at a certain power level. Undesired har- monics at the output

Wu, Hui

302

High-voltage air-core pulse transformers  

SciTech Connect

General types of air core pulse transformers designed for high voltage pulse generation and energy transfer applications are discussed with special emphasis on pulse charging systems which operate up to the multi-megavolt range. The design, operation, dielectric materials, and performance are described. It is concluded that high voltage air core pulse transformers are best suited to applications outside the normal ranges of conventional magnetic core transformers. In general these include charge transfer at high power levels and fast pulse generation with comparatively low energy. When properly designed and constructed, they are capable of delivering high energy transfer efficiency and have demonstrated superior high voltage endurance. The principal disadvantage of high voltage air core transformers is that they are not generally available from commercial sources. Consequently, the potential user must become thoroughly familiar with all aspects of design, fabrication and system application before he can produce a high performance transformer system. (LCL)

Rohwein, G. J.

1981-01-01T23:59:59.000Z

303

Eliminate Excessive In-Plant Distribution System Voltage Drops...  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

connections-can account for less than 1% to more than 4% of total plant electrical energy consumption. This two-page tip sheet recommends conducting a voltage drop survey and...

304

Optical crystal based devices for current and voltage measurement  

SciTech Connect

A prerequisite for safe, stable operation of an electric power system is accurate, reliable measurement of the system parameters, in particular, current and voltage. Traditionally this has been achieved on High Voltage (HV) systems by expensive, bulky iron-cored current transformers (CTs) and capacitor voltage transformers (VTs). Both these devices are increasingly coming under review in modern power systems due to their cost, safety implications for personnel and surrounding plant if failure occurs, installation time and indeed substation land requirements. This paper describes novel designs for magneto-optic and electro-optic crystal sensors providing potentially separate and combined current and voltage measurement. The results of testing programs are presented and details of the work associated with field trials given.

Cruden, A.; Richardson, Z.J.; McDonald, J.R.; Andonovic, I. [Univ. of Strathclyde (United Kingdom)] [Univ. of Strathclyde (United Kingdom)

1995-07-01T23:59:59.000Z

305

Design & Fabrication of a High-Voltage Photovoltaic Cell  

SciTech Connect

Silicon photovoltaic (PV) cells are alternative energy sources that are important in sustainable power generation. Currently, applications of PV cells are limited by the low output voltage and somewhat low efficiency of such devices. In light of this fact, this project investigates the possibility of fabricating high-voltage PV cells on float-zone silicon wafers having output voltages ranging from 50 V to 2000 V. Three designs with different geometries of diffusion layers were simulated and compared in terms of metal coverage, recombination, built-in potential, and conduction current density. One design was then chosen and optimized to be implemented in the final device design. The results of the simulation serve as a feasibility test for the design concept and provide supportive evidence of the effectiveness of silicon PV cells as high-voltage power supplies.

Felder, Jennifer; /North Carolina State U. /SLAC

2012-09-05T23:59:59.000Z

306

High Voltage Electrolytes for Li-ion Batteries | Department of...  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Electrolytes for Li-ion Batteries High Voltage Electrolytes for Li-ion Batteries 2011 DOE Hydrogen and Fuel Cells Program, and Vehicle Technologies Program Annual Merit Review and...

307

Long term voltage stability analysis for small disturbances  

E-Print Network (OSTI)

This dissertation attempts to establish an analytical and comprehensive framework to deal with two critical challenges associated with voltage stability analysis: 1. To study the new competitive environment appropriately and give more incentive...

Men, Kun

2009-05-15T23:59:59.000Z

308

Voltage asymmetry at the buses of a combined substation  

Science Journals Connector (OSTI)

The voltage asymmetry at the buses of a combined (ac/dc) substation is calculated by phase method, using Mathcad ... , power may be supplied to a combined substation along a common line from a limited-...

A. G. Pakulin; V. A. Zagorskii; V. F. Put’ko

2013-07-01T23:59:59.000Z

309

Operation of buck regulator with ultra-low input voltage  

E-Print Network (OSTI)

Based on the LTC3621 and LTC3624, the designed buck regulator proposed in this thesis aims to lower the allowed input voltage and increase efficiency compared to the original part without making significant changes to ...

Harris, Cory Angelo

2014-01-01T23:59:59.000Z

310

Reactive Support and Voltage Control Service: Key Issues and Challenges  

E-Print Network (OSTI)

Reactive Support and Voltage Control Service: Key Issues and Challenges George Gross^, Paolo of Illinois at Urbana-Champaign, Urbana, IL 61801, USA, e-mail gross@uiuc.edu ° Dipartimento di Ingegneria

Gross, George

311

Automotive high-voltage electrical system with integrated safeguard  

Science Journals Connector (OSTI)

For several years the use of higher system voltages has been a topic in the automotive industry. Whether for hybrid or conventional vehicles, safeguards are required which protect both the vehicle...

Thomas Flottmann

2007-03-01T23:59:59.000Z

312

Modeling the operating voltage of liquid metal battery cells  

E-Print Network (OSTI)

A one-dimensional, integrative model of the voltage during liquid metal battery operation has been developed to enhance the understanding of performance at the cell level. Two liquid metal batteries were studied: Mg-Sb for ...

Newhouse, Jocelyn Marie

2014-01-01T23:59:59.000Z

313

Voltage Fade, an ABR Deep Dive Project: Status and Outcomes  

Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

Budget * Voltage Fade project * 3,900K Barriers * Calendarcycle life of lithium-ion cells being developed for PHEV and EV batteries that meet or exceed DOEUSABC goals Partners...

314

High Voltage Electrolytes for Li-ion Batteries | Department of...  

Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

in Support of 5 V Li-ion Chemistries Vehicle Technologies Office Merit Review 2014: Fluorinated Electrolyte for 5-V Li-Ion Chemistry High Voltage Electrolyte for Lithium Batteries...

315

High voltage dry-type air-core shunt reactors  

Science Journals Connector (OSTI)

Dry-type air-core shunt reactors are now being ... systems to limit overvoltages. Recently, high voltage dry-type air-core shunt reactors have been designed, ... transient overvoltages and electrical and magnetic...

Klaus Papp; Michael R. Sharp…

2014-11-01T23:59:59.000Z

316

High-speed low-voltage ultraviolet light source  

Science Journals Connector (OSTI)

A novel quasi-spark gap has been designed and constructed with high-speed and low-spark voltage characteristics. Ultraviolet light generating sparks can be operated at a rate of up to...

Huang, L; Hsu, S C; Kwok, H S

1984-01-01T23:59:59.000Z

317

LM111/LM211/LM311 Voltage Comparator  

E-Print Network (OSTI)

LM111/LM211/LM311 Voltage Comparator 1.0 General Description The LM111, LM211 and LM311 are voltage comparators that have input currents nearly a thousand times lower than devices like the LM106 or LM710A. Both the inputs and the outputs of the LM111, LM211 or the LM311 can be isolated from system ground

Lanterman, Aaron

318

Sinusoidal voltage controlled oscillators using operational transconductance amplifiers  

E-Print Network (OSTI)

SINUSOIDAI. VOLTAGE CONTROLLED OSCILLATORS I. SING OPERATIONAL TRANSCONDUCTANCE AMPLIFIERS A Thesis JAVIFB . IOAQUIN HOYI. K I'ASSANO Suhndtted to the Graduate College ol' 'I'exes A8cM University in partial fulfillment of the requirement... for the degree of MASTER OF SCIENCE May 1985 Major Subject: Electrical Engineering SINUSOIDAL VOLTAGE CONTROLLED OSCILLATORS USING OPERATIONAI, TRANSCONDUCTANCE AMPLIFIERS A Thesis by JAVIER JOAQUIN HOYLE PASSANO Approved as to style and content by: o...

Hoyle Passano, Javier Joaquin

1985-01-01T23:59:59.000Z

319

Image-line voltage controlled oscillators and grating antennas  

E-Print Network (OSTI)

IMAGE-LINE VOLTAGE CONTROLLED OSCILLATORS AND GRATING ANTENNAS A Thesis by ALEXANDER MacDONALD KIRK Submitted to the Office of Graduate Studies of Texas ABM University in partial fulfillment of the requirements for the degree of MASTER... OF SCIENCE May 1991 Major Subject: Electrical Engineering IMAGE-LINE VOLTAGE CONTROLLED OSCILLATORS AND GRATING ANTENNAS A Thesis by ALEXANDER MacDONALD KIRK Approved as to style and content by: Kai Chang (Chair of Committee) Robert D. Nevels...

Kirk, Alexander MacDonald

1991-01-01T23:59:59.000Z

320

Design issues for high voltage converters for ion engines  

SciTech Connect

A design strategy is presented for a power converter for a high voltage ion engine for a spacecraft application. Various design issues such as appropriate topologies and control methods are considered. In this particular instance it was determined that a full bridge converter with phase shift gating and voltage mode control provided an efficient system with a minimum of electromagnetic interference. This system can be implemented in a straightforward manner, and it is relatively easy to protect from faults at the output.

King, R.J.; Stuart, T.A. [Univ. of Toledo, OH (United States)

1995-12-31T23:59:59.000Z

Note: This page contains sample records for the topic "frequency variable voltage" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


321

Centralized wind power plant voltage control with optimal power flow algorithm.  

E-Print Network (OSTI)

??This thesis presents a method of controlling the reactive power injected into a medium-voltage collection system by multiple wind turbine generators such that the voltage… (more)

Kline, Jared Andrew

2011-01-01T23:59:59.000Z

322

Low Voltage Electrostatic Actuation and Displacement Measurement through Resonant Drive Circuit.  

E-Print Network (OSTI)

??An electrostatic actuator driven by conventional voltage control and charge control requires high actuation voltage and suffers from the pull-in phenomenon that limits its operation… (more)

Park, Sangtak

2011-01-01T23:59:59.000Z

323

Integrated, Low Voltage, DynamicallyIntegrated, Low Voltage, Dynamically Adaptive BuckAdaptive Buck--Boost ConverterBoost Converter  

E-Print Network (OSTI)

Improvement in battery life Low voltage Single cell operation (Li-ion/NiCd/NiMH/Fuel Cell) Integrated Linearity degradation #12;55Georgia Tech Analog Consortium Biranchinath Sahu School of Electrical

Rincon-Mora, Gabriel A.

324

System and method of modulating electrical signals using photoconductive wide bandgap semiconductors as variable resistors  

DOE Patents (OSTI)

A system and method for producing modulated electrical signals. The system uses a variable resistor having a photoconductive wide bandgap semiconductor material construction whose conduction response to changes in amplitude of incident radiation is substantially linear throughout a non-saturation region to enable operation in non-avalanche mode. The system also includes a modulated radiation source, such as a modulated laser, for producing amplitude-modulated radiation with which to direct upon the variable resistor and modulate its conduction response. A voltage source and an output port, are both operably connected to the variable resistor so that an electrical signal may be produced at the output port by way of the variable resistor, either generated by activation of the variable resistor or propagating through the variable resistor. In this manner, the electrical signal is modulated by the variable resistor so as to have a waveform substantially similar to the amplitude-modulated radiation.

Harris, John Richardson; Caporaso, George J; Sampayan, Stephen E

2013-10-22T23:59:59.000Z

325

Self isolating high frequency saturable reactor  

DOE Patents (OSTI)

The present invention discloses a saturable reactor and a method for decoupling the interwinding capacitance from the frequency limitations of the reactor so that the equivalent electrical circuit of the saturable reactor comprises a variable inductor. The saturable reactor comprises a plurality of physically symmetrical magnetic cores with closed loop magnetic paths and a novel method of wiring a control winding and a RF winding. The present invention additionally discloses a matching network and method for matching the impedances of a RF generator to a load. The matching network comprises a matching transformer and a saturable reactor.

Moore, James A. (Powell, TN)

1998-06-23T23:59:59.000Z

326

Plasma Immersion Ion Implantation with a 4kV/10kHz Compact High Voltage Pulser  

SciTech Connect

Development of a 4 kV/10 kHz Compact High Voltage Pulser and its application to nitrogen plasma immersion ion implantation (PIII) of different materials as Si, Al alloys, SS304 stainless steel and Ti alloys are discussed. Low voltage (1-5 kV) pulses at high frequencies (up to 20 kHz for 2 kV) were obtained with maximum power delivered at 5 kV, 7 kHz. These conditions were not sufficient to reach temperatures above 200 deg. C in the samples because of short duration of the pulses. However, very shallow implantations of nitrogen in Si, Al5052, SS304 were observed by Auger electron spectroscopy and improved corrosion resistance was obtained for Al5052 when it was treated by nitrogen PIII at 2.5 kV, 5{mu}s and 5 kHz pulses.

Ueda, M.; Oliveira, R. M.; Rossi, J. O. [Associated Laboratory of Plasma, National Institute for Space Research, Av. dos Astronautas 1758, Sao Jose dos Campos, Sao Paulo (Brazil); Reuther, H. [Institute of Ion Beam Physics and Materials Research, Rossendorf, Dresden (Germany); Silva, G. [Associated Laboratory of Plasma, National Institute for Space Research, Av. dos Astronautas 1758, Sao Jose dos Campos, Sao Paulo (Brazil); Department of Aeronautics and Mechanics, Technological Institute of Aeronautics, Sao Jose dos Campos, Sao Paulo (Brazil)

2006-11-13T23:59:59.000Z

327

VERY LOW FREQUENCY BREAKDOWN PROPERTIES OF ELECTRICAL INSULATION MATERIALS AT CRYOGENIC TEMPERATURES  

SciTech Connect

For long cables or equipment with large capacitance it is not always possible to conduct high voltage withstand at tests at 60 Hz due to limitations in charging currents of the power supply. Very low frequency (typically at a frequency of 0.1 Hz) has been used for conventional cables as a way of getting around the charging current limitation. For superconducting grid applications the same issues apply. However there is very little data at cryogenic temperatures on how materials perform at low frequency compared to 60 Hz and whether higher voltages should be applied when performing a high voltage acceptability test. Various materials including G10 (fiberglass reinforced plastic or FRP), Cryoflex (a tape insulation used in some high temperature superconducting cables), kapton (commonly used polyimide), polycarbonate, and polyetherimide, and in liquid nitrogen alone have been tested using a step method for frequencies of 60 Hz, 0.1 Hz, and dc. The dwell time at each step was chosen so that the aging factor would be the same in both the 60 Hz and 0.1 Hz tests. The data indicated that, while there is a small frequency dependence for liquid nitrogen, there are significant differences for the solid materials studied. Breakdown data for these materials and for model cables will be shown and discussed.

Sauers, Isidor [ORNL; Tuncer, Enis [ORNL; Polyzos, Georgios [ORNL; James, David Randy [ORNL; Ellis, Alvin R [ORNL; Pace, Marshall O [ORNL

2010-01-01T23:59:59.000Z

328

Response of radio frequency superconducting quantum interference devices to electromagnetic interference  

SciTech Connect

A number of applications of high-temperature superconductor radio frequency superconducting quantum interference devices (rf SQUIDs) require a certain immunity of these sensors against electromagnetic interference (EMI). We have investigated effects of electromagnetic radiation in the high-frequency and ultrahigh-frequency range on various types of rf SQUIDs. It has been found that EMI of sufficient field strength reduces the voltage versus flux transfer function, and thus increases the flux noise of the SQUIDs. SQUIDs with a wire wound tank circuit coil have been found to be more sensitive to EMI than SQUIDs integrated into a superconducting microstrip resonator. {copyright} {ital 1995} {ital American} {ital Institute} {ital of} {ital Physics}.

Mueck, M.; Dechert, J.; Gail, J.; Kreutzbruck, M.; Schoene, S.; Weidl, R. [Institut fuer Angewandte Physik, Justus-Liebig-Universitaet Giessen, Heinrich-Buff-Ring 16, 35392 Giessen (Germany)] [Institut fuer Angewandte Physik, Justus-Liebig-Universitaet Giessen, Heinrich-Buff-Ring 16, 35392 Giessen (Germany)

1995-09-01T23:59:59.000Z

329

Seasonal Forecasting of Extreme Wind and Precipitation Frequencies in Europe  

E-Print Network (OSTI)

Seasonal Forecasting of Extreme Wind and Precipitation Frequencies in Europe Matthew J. Swann;Abstract Flood and wind damage to property and livelihoods resulting from extreme precipitation events variability of these extreme events can be closely related to the large-scale atmospheric circulation

Feigon, Brooke

330

The frequency dependent impedance of an HVdc converter  

SciTech Connect

A linear and direct method of determining the frequency dependent impedance of a 12 pulse HVdc converter is presented. Terms are developed for both the dc and ac side impedances of the converter, including the effect of the firing angle control system, the commutation period, and the variability of the commutation period. The impedance predictions are verified by dynamic simulation.

Wood, A.R.; Arrillaga, J. [Univ. of Canterbury, Christchurch (New Zealand)] [Univ. of Canterbury, Christchurch (New Zealand)

1995-07-01T23:59:59.000Z

331

HV Substation Overvoltage Computation Taking into Account Frequency Dependent Transients on the Substation Grounding System  

E-Print Network (OSTI)

Abstract-This paper describes methodology for the computation of the electromagnetic transients in the high voltage substations, taking into account transients on the substation grounding system. Simulation technology is based on the system decomposition. Interconnections between different subsystems are done in each time step using Thevenin equivalents. Frequency dependent impedance of grounding conductors is represented by the parallel combination of resistance-inductance branches, to enable simulation in the time domain. Lightning overvoltage computation is performed for one particular 123 kV high voltage substation.

unknown authors

332

Low frequency noise behavior in a-Si:H Schottky barrier devices  

SciTech Connect

The authors present a systematic experimental study of low frequency noise behavior in Mo/a-Si:H Schottky diodes under reverse bias operation. The noise in the Schottky diode was found to increase with increasing reverse current and with an approximate 1/f behavior at low bias voltages, yielding a Hooge parameter in the range (2 to 3) {times} 10{sup {minus}4}. At high reverse voltages, due to electrical stressing and hence, bias-induced material instability, a significant deviation from the 1/f behavior was observed.

Aflatooni, K.; Nathan, A.; Hornsey, R. [Univ. of Waterloo, Ontario (Canada). Electrical and Computer Engineering

1996-12-31T23:59:59.000Z

333

Modeling the High-Frequency Component of Arctic Sea Ice Drift and Deformation  

Science Journals Connector (OSTI)

Buoy observations of sea ice drift show that sea ice motion and deformation contain substantial high-frequency variability at subdaily timescales. However, numerical simulations of the sea ice dynamics normally do not include processes on such ...

Petra Heil; William D. Hibler III

2002-11-01T23:59:59.000Z

334

Minimization of voltage deviation and power losses in power networks using Pareto optimization methods  

Science Journals Connector (OSTI)

Voltage regulation is an important task in electrical engineering for controlling node voltages in a power network. A widely used solution for the problem of voltage regulation is based on adjusting the taps in under load tap changers (ULTCs) power transformers ... Keywords: Multi-objective optimization, Power distribution network, Power losses, Under load tap changers, Voltage regulation

Francisco G. Montoya; Raúl Bańos; Consolación Gil; Antonio Espín; Alfredo Alcayde; Julio Gómez

2010-08-01T23:59:59.000Z

335

Requirements for a Standard Test to Rate the Durability of PV Modules at System Voltage (Presentation)  

SciTech Connect

Degradation modes in photovoltaic modules under system bias voltage stress are described and classified.

Hacke, P.; Terwilliger, K.; Glick, S.; Kempe, M.; Kurtz, S.; Bennett, I.; Kloos, M.

2011-02-01T23:59:59.000Z

336

Summaries of Addresses of Presidents of Sections: High-Voltage Insulation  

Science Journals Connector (OSTI)

... subject of his presidential address to Section A (Mathematics and Physics) *'High-voltage Insulation".

1963-08-31T23:59:59.000Z

337

Elevated voltage level I.sub.DDQ failure testing of integrated circuits  

DOE Patents (OSTI)

Burn in testing of static CMOS IC's is eliminated by I.sub.DDQ testing at elevated voltage levels. These voltage levels are at least 25% higher than the normal operating voltage for the IC but are below voltage levels that would cause damage to the chip.

Righter, Alan W. (Albuquerque, NM)

1996-01-01T23:59:59.000Z

338

Elevated voltage level I{sub DDQ} failure testing of integrated circuits  

DOE Patents (OSTI)

Burn in testing of static CMOS IC`s is eliminated by I{sub DDQ} testing at elevated voltage levels. These voltage levels are at least 25% higher than the normal operating voltage for the IC but are below voltage levels that would cause damage to the chip. 4 figs.

Righter, A.W.

1996-05-21T23:59:59.000Z

339

Graz University of Technology Institute of High Voltage Engineering and System Performance  

E-Print Network (OSTI)

.hspt@tugraz.at u www.hspt.tugraz.at Institute of High Voltage Engineering and System Performance Test Laboratory systems Test of insulators, fittings and accessories Testing of high voltage equipment Impulse voltage and current tests On-site-test of medium voltage cables Electrical methods in environmental technology

340

Method and Appartus for Calibrating a Linear Variable Differential Transformer  

SciTech Connect

A calibration apparatus for calibrating a linear variable differential transformer (LVDT) having an armature positioned in au LVDT armature orifice, and the armature able to move along an axis of movement. The calibration apparatus includes a heating mechanism with an internal chamber, a temperature measuring mechanism for measuring the temperature of the LVDT, a fixture mechanism with an internal chamber for at least partially accepting the LVDT and for securing the LVDT within the heating mechanism internal chamber, a moving mechanism for moving the armature, a position measurement mechanism for measuring the position of the armature, and an output voltage measurement mechanism. A method for calibrating an LVDT, including the steps of powering the LVDT; heating the LVDT to a desired temperature; measuring the position of the armature with respect to the armature orifice; and measuring the output voltage of the LVDT.

Pokrywka, Robert J.

2005-01-18T23:59:59.000Z

Note: This page contains sample records for the topic "frequency variable voltage" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


341

Method and apparatus for calibrating a linear variable differential transformer  

DOE Patents (OSTI)

A calibration apparatus for calibrating a linear variable differential transformer (LVDT) having an armature positioned in au LVDT armature orifice, and the armature able to move along an axis of movement. The calibration apparatus includes a heating mechanism with an internal chamber, a temperature measuring mechanism for measuring the temperature of the LVDT, a fixture mechanism with an internal chamber for at least partially accepting the LVDT and for securing the LVDT within the heating mechanism internal chamber, a moving mechanism for moving the armature, a position measurement mechanism for measuring the position of the armature, and an output voltage measurement mechanism. A method for calibrating an LVDT, including the steps of: powering the LVDT; heating the LVDT to a desired temperature; measuring the position of the armature with respect to the armature orifice; and measuring the output voltage of the LVDT.

Pokrywka, Robert J. (North Huntingdon, PA)

2005-01-18T23:59:59.000Z

342

Experiment Hazard Class 13.0 - High Voltage  

NLE Websites -- All DOE Office Websites (Extended Search)

3.0 - High Voltage 3.0 - High Voltage Applicability This hazard classification applies to all experiments involving the use of High Voltage Equipment. Other hazard classifications and their associated hazard controls may also apply to experiments in this hazard class. The inspection of electric equipment is covered under the APS Policy For User Electric Equipment Inspections. NOTE: Unless required Argonne training has been completed, users are not authorized to perform electrical work. Experiment Category All Hazard Class 13 experiments are categorized as medium risk experiments. Experiment Hazard Control Verification Statements Engineered Controls - Determined by review and results of a DEEI inspection of the equipment. Procedural Controls - Determined by review and results of a DEEI

343

High voltage stability performance of a gamma ray detection device  

SciTech Connect

An industrial grade digital radiation survey meter device is currently being developed at Malaysian Nuclear Agency. This device used a cylindrical type Geiger Mueller (GM) which acts as a detector. GM detector operates at relatively high direct current voltages depend on the type of GM tube. This thin/thick walled cylindrical type of GM tube operates at 450-650 volts range. Proper value and stability performance of high voltage are important parameters to ensure that this device give a reliable radiation dose measurement. This paper will present an assessment of the stability and performance of the high voltage supply for radiation detector. The assessment is performed using System Identification tools box in MATLAB and mathematical statistics.

Abdullah, Nor Arymaswati; Lombigit, Lojius; Rahman, Nur Aira Abd [Technical Support Division, Malaysian Nuclear Agency, 43000 Kajang, Selangor (Malaysia)

2014-02-12T23:59:59.000Z

344

Voltage Impacts of Utility-Scale Distributed Wind  

SciTech Connect

Although most utility-scale wind turbines in the United States are added at the transmission level in large wind power plants, distributed wind power offers an alternative that could increase the overall wind power penetration without the need for additional transmission. This report examines the distribution feeder-level voltage issues that can arise when adding utility-scale wind turbines to the distribution system. Four of the Pacific Northwest National Laboratory taxonomy feeders were examined in detail to study the voltage issues associated with adding wind turbines at different distances from the sub-station. General rules relating feeder resistance up to the point of turbine interconnection to the expected maximum voltage change levels were developed. Additional analysis examined line and transformer overvoltage conditions.

Allen, A.

2014-09-01T23:59:59.000Z

345

Frequency Scalable Non-Linear Waveform Generator for Mixed-Simal Power-Factor-Correction IC Controller'  

E-Print Network (OSTI)

operates with a fixed switching frequency fs and variable duty ratio R, and can be analyzed using standard of a switching period, a fixed-frequency clock pulse sets the switch drive high. A signal proportionalFrequency Scalable Non-Linear Waveform Generator for Mixed-Simal Power-Factor-Correction IC

346

The XRCC1 399Gln Polymorphism and the Frequency of p53 Mutations in Taiwanese Oral Squamous Cell Carcinomas  

Science Journals Connector (OSTI)

...association with the frequency of p53 mutation...genetic lesions that drive human carcinogenesis...significantly increased the frequency of p53 mutations...399 genotype and the frequency of p53 gene mutation Variable Gln/Gln Gln/Arg...

Ling-Ling Hsieh; Huei-Tzu Chien; I-How Chen; Chun-Ta Liao; Hung-Ming Wang; Shih-Ming Jung; Pei-Feng Wang; Joseph Tung-Chieh Chang; Min-Chi Chen; and Ann-Joy Cheng

2003-05-01T23:59:59.000Z

347

Improving the low voltage ride through of doubly fed induction generator during intermittent voltage source converter faults  

Science Journals Connector (OSTI)

The impact of different voltage source converter (VSC) faults on the low voltage ride through (LVRT) capability of the doubly fed induction generator (DFIG) is also investigated. Faults such as fire-through of the VSC switches and short circuit across the DC-link capacitor are considered in this paper. The impact of internal VSC faults when they occur within the grid side converter (GSC) and rotor side converter is investigated. A proper static synchronous compensator (STATCOM) controller to mitigate the effects of these faults is proposed. The DFIG compliance with numerous and recently released LVRT grid codes under these faults with and without the STATCOM is examined and compared. Simulation results indicate that these types of faults have a severe impact on the DFIG voltage profile especially when these faults occur in the GSC. This is attributed to the fact that the GSC directly regulates the point of common coupling (PCC) voltage. Moreover the proposed controller is capable of bringing the voltage profile at the PCC to the nominal steady state level and hence maintaining the connection of the wind turbine during the various studied faults.

H. R. Pota

2013-01-01T23:59:59.000Z

348

Voltage Control Devices on the IEEE 8500 Node Test Feeder  

SciTech Connect

The IEEE Test Cases provide researchers with distribution system models that can be used to validate new analytic methods. The newest of these models is the 8500-node test feeder which contains multiple devices for voltage control. In addition to a substation regulator there are multiple inline regulators as well as capacitor banks. This paper will discuss the detail in which voltage control devises should be modeled when examining large distribution systems. This discussion will include issues associated with power flow analysis for a single time step as well as for time series analysis.

Schneider, Kevin P.; Fuller, Jason C.

2010-01-06T23:59:59.000Z

349

Reduction of interference on substation low voltage wiring  

SciTech Connect

This paper describes test results and mitigation methods of electromagnetic interference (EMI) on control and low voltage circuits in substations caused by air disconnect switch operation. The tests are focused on a comparison between unshielded and shielded circuits from capacitively coupled voltage transformers (CCVT) and other equipment circuits in the vicinity. New test data are presented comparing unshielded and shielded cables and transient currents on all connections to the CCVT including the pedestal and ground strap. The paper gives a practical and understandable explanation of the causes of EMI in substations and how shielded cable and parallel ground conductors reduce interference. Design guidelines are listed in the Conclusion.

Gavazza, R.J. [Pacific Gas and Electric Co., San Francisco, CA (United States)] [Pacific Gas and Electric Co., San Francisco, CA (United States); Wiggins, C.M. [Carl M. Wiggins and Associates, Friendswood, TX (United States)] [Carl M. Wiggins and Associates, Friendswood, TX (United States)

1996-07-01T23:59:59.000Z

350

Conditions for Capacitor Voltage Regulation in a Five-Level Cascade Multilevel Inverter: Application to Voltage-Boost in a PM Drive  

E-Print Network (OSTI)

Conditions for Capacitor Voltage Regulation in a Five-Level Cascade Multilevel Inverter Abstract-- A cascade multilevel inverter is a power electronic device built to synthesize a desired AC voltage from several levels of DC voltages. Such inverters have been the subject of research in the last

Tolbert, Leon M.

351

Integral variable structure current control of DFIG-based wind turbines near cut-in speed  

Science Journals Connector (OSTI)

Based on the grid voltage orientated vector control technique, a novel integral variable structure controller for current control of variable speed doubly fed induction generator (DFIG) wind turbines near cut-in wind speed is proposed. The proposed current controller can not only ensure generators' safe cut-in switches to the grid, but also maximum energy capture after switch motion without any regulations. By these, simulations of a 1.5 MW DFIG-based wind turbine near cut-in wind speed are separately conducted under integral variable structure control (IVSC) and PI control. The results show that IVSC strategy, which gives better dynamic response, less static error, smaller controller output dithering, stronger global robustness against generator parameters uncertainty and the grid voltage fluctuation, as well as needless controller regulation after cutting-in the grid, obviously preponderates over traditional PI control for DFIG-based wind turbines near cut-in speed.

Changliang Xia; Huimin Wang; Zhanfeng Song

2009-01-01T23:59:59.000Z

352

Effect of Microwave Frequency on Hydrothermal Synthesis of Nanocrystalline Tetragonal Barium Titanate  

E-Print Network (OSTI)

Effect of Microwave Frequency on Hydrothermal Synthesis of Nanocrystalline Tetragonal Barium) with particle sizes ranging from 30 to 100 nm were synthesized via microwave-hydrothermal routes at various, but increased gradually with extended aging time in variable frequency (3-5.5 GHz to 1 s) processing

Dutta, Prabir K.

353

Detectable Changes in the Frequency of Temperature Extremes SIMONE MORAK AND GABRIELE C. HEGERL  

E-Print Network (OSTI)

Detectable Changes in the Frequency of Temperature Extremes SIMONE MORAK AND GABRIELE C. HEGERL of hot and cold extremes over land can be explained by climate variability or whether they show a detectable response to external influences. The authors analyze changes in the frequency of moderate-to-extreme

Hegerl, Gabriele Clarissa "Gabi"

354

Low Beam Voltage, 10 MW, L-Band Cluster Klystron  

SciTech Connect

Conceptual design of a multi-beam klystron (MBK) for possible ILC and Project X applications is presented. The chief distinction between this MBK design and existing 10-MW MBK's is the low operating voltage of 60 kV. There are at least four compelling reasons that justify development at this time of a low-voltage MBK, namely (1) no pulse transformer; (2) no oil tank for high-voltage components and for the tube socket; (3) no high-voltage cables; and (4) modulator would be a compact 60-kV IGBT switching circuit. The proposed klystron consists of four clusters containing six beams each. The tube has common input and output cavities for all 24 beams, and individual gain cavities for each cluster. A closely related optional configuration, also for a 10 MW tube, would involve four totally independent cavity clusters with four independent input cavities and four 2.5 MW output ports, all within a common magnetic circuit. This option has appeal because the output waveguides would not require a controlled atmosphere, and because it would be easier to achieve phase and amplitude stability as required in individual SC accelerator cavities.

Teryaev, V.; /Novosibirsk, IYF; Yakovlev, V.P.; /Fermilab; Kazakov, S.; /KEK, Tsukuba; Hirshfield, J.L.; /Yale U. /Omega-P, New Haven

2009-05-01T23:59:59.000Z

355

Power Grid Voltage Integrity Verification Department of ECE  

E-Print Network (OSTI)

Power Grid Voltage Integrity Verification Maha Nizam Department of ECE University of Toronto devgan@magma-da.com ABSTRACT Full-chip verification requires one to check if the power grid is safe, i of the circuit attached to the grid, thereby precluding early verification of the grid. We propose a power grid

Najm, Farid N.

356

Voltage Regulation through Smart Utilization of Potential Reactive Power Resources  

Science Journals Connector (OSTI)

The introduction of demand response concept, in addition to increment of penetration of distributed generation (DG) based on renewable energies, make opportunities for the novel control schemes to be integrated in power system on a smart grid framework. ... Keywords: Demand response, distributed generation, reactive power, renewable energy, smart grid, voltage control

H. Kazari; A. Abbaspour-Tehrani Fard; A. S. Dobakhshari; A. M. Ranjbar

2011-11-01T23:59:59.000Z

357

ORIGINAL ARTICLES Induced Transmembrane Voltage and Its Correlation  

E-Print Network (OSTI)

to investigate the correlation between DWm and molecular transport through an elec- troporated membrane to a voltage (electric potential difference) caused by a system of ion pumps and channels in the membrane, or electropermea- bilization, and permits transmembrane transport of mole- cules for which an intact membrane

Ljubljana, University of

358

Topical Review Voltage Dependence of the Na/K Pump  

E-Print Network (OSTI)

or ``ion well'' hy- pothesis. There are only two ways that net transport can be voltage dependent. Either of the external Na+ and K+ bind- ing sites within the membrane field. This access channel or ``ion well produced by applying a blocking Key words: Na,K-ATPase -- Membrane potential -- Access channel -- Ion well

Gadsby, David

359

Current isolating epitaxial buffer layers for high voltage photodiode array  

DOE Patents (OSTI)

An array of photodiodes in series on a common semi-insulating substrate has a non-conductive buffer layer between the photodiodes and the semi-insulating substrate. The buffer layer reduces current injection leakage between the photodiodes of the array and allows optical energy to be converted to high voltage electrical energy.

Morse, Jeffrey D. (Martinez, CA); Cooper, Gregory A. (Pleasant Hill, CA)

2002-01-01T23:59:59.000Z

360

Load Balancing in Wireless Sensor Networks using Kirchhoff's Voltage Law  

E-Print Network (OSTI)

Load Balancing in Wireless Sensor Networks using Kirchhoff's Voltage Law Stavros Toumpis Electrical balancing in wireless networks with a single class of traffic, focusing our attention on an important example, i.e., Wireless Sensor Networks. The analysis is based on the Wireless Minimum Cost Problem

Toumpis, Stavros

Note: This page contains sample records for the topic "frequency variable voltage" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


361

Power and Voltage Smooth Control of Doubly Fed Induction Generator  

Science Journals Connector (OSTI)

Doubly-fed induction generator (DFIG) is the leading in wind power technology currently. In this paper, decoupling control of DFIG is studied and a new energy storage device is used in the smooth control of DFIG system's power and voltage. This new method ... Keywords: Doubly fed induction generator, Energy storage device, Decoupling control

An-Ren Ma; Cai-Xia Wang; Zhi-Wen Zhou; Tao Wu

2012-07-01T23:59:59.000Z

362

Analysis on DFIG Wind Power System Low-Voltage Ridethrough  

Science Journals Connector (OSTI)

Due to the double fed induction generator’s (DFIG) advantage of controlling active and reactive power independently and partial power converter, DFIG is becoming a popular type of wind power generation system. Nowadays, the grid code demands that ... Keywords: VSCF, DFIG, LVRT, Crowbar, Voltage sags

Yulong Wang; Jianlin Li; Shuju Hu; Honghua Xu

2009-04-01T23:59:59.000Z

363

SVC Voltage Regulator Based on Fractional Order PID  

Science Journals Connector (OSTI)

Contradiction exist between rapid and smooth in the dynamic adjustment process of SVC, however, Fractional order PID controller has two degrees of freedom more than the integer order PID controller, and it has better control performance. This article ... Keywords: SVC, Fractional order PID, Voltage regulator, Oustaloup

Manyu Liu; Huaying Dong; Guishu Liang

2012-12-01T23:59:59.000Z

364

Way to reduce arc voltage losses in hybrid thermionic converters  

SciTech Connect

Experimental results are reported concerning the output and emission characteristics of the arc and hybrid regimes in a plane-parallel thermionic converter with Pt--Zr--O electrode pair. It is shown that arc voltage losses can be reduced to values below those obtainable in ordinary arc thermionic converters.

Tskhakaya, V.K.; Yarygin, V.I.

1982-03-01T23:59:59.000Z

365

Field Optimization of Three Dimensional High Voltage C. Trinitis  

E-Print Network (OSTI)

Field Optimization of Three Dimensional High Voltage Equipment C. Trinitis Lehrstuhl f The goal of finding an optimal electric field strength distribution for arbitrary three di­ mensional­ cal optimization algorithm. The package ob­ tained from these three components is then able

Stamatakis, Alexandros

366

High voltage gas insulated transmission line with continuous particle trapping  

DOE Patents (OSTI)

This invention provides a novel high voltage gas insulated transmission line utilizing insulating supports spaced at intervals with snap-in means for supporting a continuous trapping apparatus and said trapping apparatus having perforations and cutouts to facilitate trapping of contaminating particles and system flexibility.

Cookson, Alan H. (Pittsburgh, PA); Dale, Steinar J. (Monroeville, PA)

1983-01-01T23:59:59.000Z

367

High Voltage DC Transmission 2 1.0 Introduction  

E-Print Network (OSTI)

1 High Voltage DC Transmission 2 1.0 Introduction Interconnecting HVDC within an AC system requires on use of switching devices collectively referred to in the HVDC community as valves. Valves may be non. Fig. 1 There have been three types of devices for implementing HVDC converter circuits: mercury

McCalley, James D.

368

North American Power Symposium NAPS, Laramie, Wyoming, October 1997, pp. 49 54. Fundamental Frequency Model of Static Synchronous Compensator  

E-Print Network (OSTI)

North American Power Symposium NAPS, Laramie, Wyoming, October 1997, pp. 49 54. Fundamental collapse studies, that required accurate representation of fundamental frequency operation and control on the utilization of high-current, high-voltage power electronic controllers 1, 2, 3, 4 . The authors in 2, 3

Cañizares, Claudio A.

369

Frequency locking in the injection-locked frequency divider equation  

E-Print Network (OSTI)

We consider a model for the injection-locked frequency divider, and study analytically the locking onto rational multiples of the driving frequency. We provide explicit formulae for the width of the plateaux appearing in the devil's staircase structure of the lockings, and in particular show that the largest plateaux correspond to even integer values for the ratio of the frequency of the driving signal to the frequency of the output signal. Our results prove the experimental and numerical results available in the literature.

Bartuccelli, Michele V; Gentile, Guido

2008-01-01T23:59:59.000Z

370

Variable depth core sampler  

DOE Patents (OSTI)

A variable depth core sampler apparatus comprising a first circular hole saw member, having longitudinal sections that collapses to form a point and capture a sample, and a second circular hole saw member residing inside said first hole saw member to support the longitudinal sections of said first hole saw member and prevent them from collapsing to form a point. The second hole saw member may be raised and lowered inside said first hole saw member.

Bourgeois, Peter M. (Hamburg, NY); Reger, Robert J. (Grand Island, NY)

1996-01-01T23:59:59.000Z

371

Variable laser attenuator  

DOE Patents (OSTI)

The disclosure relates to low loss, high power variable attenuators comprising one or more transmissive and/or reflective multilayer dielectric filters. The attenuator is particularly suitable to use with unpolarized lasers such as excimer lasers. Beam attenuation is a function of beam polarization and the angle of incidence between the beam and the filter and is controlled by adjusting the angle of incidence the beam makes to the filter or filters. Filters are selected in accordance with beam wavelength. 9 figs.

Foltyn, S.R.

1987-05-29T23:59:59.000Z

372

Variable depth core sampler  

DOE Patents (OSTI)

A variable depth core sampler apparatus is described comprising a first circular hole saw member, having longitudinal sections that collapses to form a point and capture a sample, and a second circular hole saw member residing inside said first hole saw member to support the longitudinal sections of said first hole saw member and prevent them from collapsing to form a point. The second hole saw member may be raised and lowered inside said first hole saw member. 7 figs.

Bourgeois, P.M.; Reger, R.J.

1996-02-20T23:59:59.000Z

373

Sensors and Actuators A 132 (2006) 139146 MEMS based digital variable capacitors with a high-k dielectric insulator  

E-Print Network (OSTI)

; Digital variable capacitor; High-k dielectric; Charge injection 1. Introduction Radio-frequency (RF]. The other one is the area tuning variable capacitor typically using a comb-drive structure which is normallySensors and Actuators A 132 (2006) 139­146 MEMS based digital variable capacitors with a high

Fleck, Norman A.

374

Light beam frequency comb generator  

DOE Patents (OSTI)

A light beam frequency comb generator uses an acousto-optic modulator to generate a plurality of light beams with frequencies which are uniformly separated and possess common noise and drift characteristics. A well collimated monochromatic input light beam is passed through this modulator to produce a set of both frequency shifted and unshifted optical beams. An optical system directs one or more frequency shifted beams along a path which is parallel to the path of the input light beam such that the frequency shifted beams are made incident on the modulator proximate to but separated from the point of incidence of the input light beam. After the beam is thus returned to and passed through the modulator repeatedly, a plurality of mutually parallel beams are generated which are frequency-shifted different numbers of times and possess common noise and drift characteristics.

Priatko, Gordon J. (Cupertino, CA); Kaskey, Jeffrey A. (Livermore, CA)

1992-01-01T23:59:59.000Z

375

Effective switching frequency multiplier inverter  

DOE Patents (OSTI)

A switching frequency multiplier inverter for low inductance machines that uses parallel connection of switches and each switch is independently controlled according to a pulse width modulation scheme. The effective switching frequency is multiplied by the number of switches connected in parallel while each individual switch operates within its limit of switching frequency. This technique can also be used for other power converters such as DC/DC, AC/DC converters.

Su, Gui-Jia (Oak Ridge, TN); Peng, Fang Z. (Okemos, MI)

2007-08-07T23:59:59.000Z

376

High-voltage supply for neutron tubes in well-logging applications  

DOE Patents (OSTI)

A high voltage supply is provided for a neutron tube used in well logging. The biased pulse supply of the invention combines DC and full pulse techniques and produces a target voltage comprising a substantial negative DC bias component on which is superimposed a pulse whose negative peak provides the desired negative voltage level for the neutron tube. The target voltage is preferably generated using voltage doubling techniques and employing a voltage source which generates bipolar pulse pairs having an amplitude corresponding to the DC bias level.

Humphreys, D.R.

1982-09-15T23:59:59.000Z

377

Audio-Frequency Power Measurements  

Science Journals Connector (OSTI)

... " prepared by the National Physical Laboratory, Teddington, is a brief pamphlet dealing with "Audio-Frequency Power Measurements" (pp. 16. London: H.M.S.O., 1954; ...

1955-09-10T23:59:59.000Z

378

Dynamic characteristics of an orthogonal turbine and output-control systems for TPP with high-voltage frequency converter  

SciTech Connect

A mathematical description of a closed control system with allowance for pressure fluctuations in the head system, which makes it possible to analyze the regime stability of orthogonal generating sets at tidal electric power plants when operating in the complete range of heads, outputs, and rotational speeds, and to select parameters of the control system, is obtained for an orthogonal hydroturbine and a generator with a load regulator.

Berlin, V. V.; Murav'ev, O. A.; Golubev, A. V.

2012-03-15T23:59:59.000Z

379

A study on current characteristics of induction motor while operating at its base frequency in textile industry  

Science Journals Connector (OSTI)

Abstract In the increasing amounts of three-phase squirrel-cage induction motors over the years are fed by variable-speed drives in majority of the industries. This paper deals about the current and power characteristics of induction motor while it operating at its base frequency with variable speed drive. Various studies have been conducted in textile industry to prove the above phenomena. When the motor runs at its base frequency through VFD (variable-frequency drive), considerable energy saving is possible. In this study, around 3.6 units saved for one operating cycle of Ringframe machine in textile industry.

Y. Dhayaneswaran; L. Ashok Kumar

2014-01-01T23:59:59.000Z

380

CFB3 Fig. 1. (a)Blockdiagramfor frequency-domain photoconductive sampling. (b) LTG-  

E-Print Network (OSTI)

a4 w, CFB3 Fig. 1. (a)Blockdiagramfor frequency- domain photoconductive sampling. (b) LTG- Ga.05-26.5 GHz). cwdiodelasers h 1000 G wg 800 F E 600 8. .E 400 * 1 2 4 6 810 dc voltage(V) CFB3 Fig. 2. 4.5-GHz.C. Nuss, IEEE Circuits Devices Mag. 12,25(1996). 2. MTT-45, 1301(1997). 3. 4. CFB4 (Invited) 8:45 am High

Bowers, John

Note: This page contains sample records for the topic "frequency variable voltage" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


381

Low-frequency RF Coupling To Unconventional (Fat Unbalanced) Dipoles  

SciTech Connect

The report explains radio frequency (RF) coupling to unconventional dipole antennas. Normal dipoles have thin equal length arms that operate at maximum efficiency around resonance frequencies. In some applications like high-explosive (HE) safety analysis, structures similar to dipoles with ''fat'' unequal length arms must be evaluated for indirect-lightning effects. An example is shown where a metal drum-shaped container with HE forms one arm and the detonator cable acts as the other. Even if the HE is in a facility converted into a ''Faraday cage'', a lightning strike to the facility could still produce electric fields inside. The detonator cable concentrates the electric field and carries the energy into the detonator, potentially creating a hazard. This electromagnetic (EM) field coupling of lightning energy is the indirect effect of a lightning strike. In practice, ''Faraday cages'' are formed by the rebar of the concrete facilities. The individual rebar rods in the roof, walls and floor are normally electrically connected because of the construction technique of using metal wire to tie the pieces together. There are two additional requirements for a good cage. (1) The roof-wall joint and the wall-floor joint must be electrically attached. (2) All metallic penetrations into the facility must also be electrically connected to the rebar. In this report, it is assumed that these conditions have been met, and there is no arcing in the facility structure. Many types of detonators have metal ''cups'' that contain the explosives and thin electrical initiating wires, called bridge wires mounted between two pins. The pins are connected to the detonator cable. The area of concern is between the pins supporting the bridge wire and the metal cup forming the outside of the detonator. Detonator cables usually have two wires, and in this example, both wires generated the same voltage at the detonator bridge wire. This is called the common-mode voltage. The explosive component inside a detonator is relatively sensitive, and any electrical arc is a concern. In a safety analysis, the pin-to-cup voltage, i.e., detonator voltage, must be calculated to decide if an arc will form. If the electric field is known, the voltage between any two points is simply the integral of the field along a line between the points. Eq. 1.1. For simplicity, it is assumed that the electric field and dipole elements are aligned. Calculating the induced detonator voltage is more complex because of the field concentration caused by metal components. If the detonator cup is not electrically connected to the metal HE container, the portion of the voltage generated by the dipole at the detonator will divide between the container-to-cup and cup-to-pin gaps. The gap voltages are determined by their capacitances. As a simplification, it will be assumed the cup is electrically attached, short circuited, to the HE container. The electrical field in the pin-to-cup area is determined by the field near the dipole, the length of the dipole, the shape of the arms, and the orientation of the arms. Given the characteristics of a lightning strike and the inductance of the facility, the electric fields in the ''Faraday cage'' can be calculated. The important parameters for determining the voltage in an empty facility are the inductance of the rebars and the rate of change of the current, Eq. 1.3. The internal electric fields are directly related to the facility voltages, however, the electric fields in the pin-to-cup space is much higher than the facility fields because the antenna will concentrate the fields covered by the arms. Because the lightning current rise-time is different for every strike, the maximum electric field and the induced detonator voltage should be described by probability distributions. For pedantic purposes, the peak field in the simulations will be simply set to 1 V/m. Lightning induced detonator voltages can be calculated by scaling up with the facility fields. Any metal object around the explosives, such as a work stand, will also distort the electric

Ong, M M; Brown, C G; Perkins, M P; Speer, R D; Javedani, J B

2010-12-07T23:59:59.000Z

382

Analysis of Heart Rate Variability Using Time-Varying Filtering of Heart Transplanted Patients  

E-Print Network (OSTI)

Analysis of Heart Rate Variability Using Time-Varying Filtering of Heart Transplanted Patients the heart rate variability (HRV), obtained by using the time-varying integral pulse frequency modulation (TVIPFM) which is well adapted to the exercise stress testing. We consider that the mean heart period

Paris-Sud XI, Université de

383

Florida Current transport variability: An analysis of annual and longer-period signals  

E-Print Network (OSTI)

n f o Article history: Received 23 June 2009 Received in revised form 9 December 2009 Accepted 7 scale variability given the strong higher frequency energy present. The annual cycle represents less variability. Comparison of the Florida Current, NAO and wind stress curl records shows that a recently

384

Wind- versus Eddy-Forced Regional Sea Level Trends and Variability in the North Pacific Ocean  

Science Journals Connector (OSTI)

Regional sea level trend and variability in the Pacific Ocean have often been considered to be induced by low-frequency surface wind changes. In this study, we demonstrate that significant sea level trend and variability can also be generated by ...

Bo Qiu; Shuiming Chen; Lixin Wu; Shinichiro Kida

385

Guidelines for Working at Voltages < 240 Volts  

NLE Websites -- All DOE Office Websites (Extended Search)

Guidelines for Working at Voltages < 240 Volts Guidelines for Working at Voltages < 240 Volts February 4, 2005---DRAFT NOTE: Working hot is a LAST ALTERNATIVE. Electrical hot work is defined as: Working on or near exposed conducting parts that are or might become energized at 50V or more. Refer to Electrical Safety Flowchart for Working On or Near Live Parts. Engineered methods to prevent exposed sources of 50V and greater are to be implemented wherever practical. Only QUALIFIED PERSONNEL {as defined in NFPA 70E Article 110.6(D) 2004 edition} as authorized by the CAT/supervisor/division can perform such work. Refer to Qualified Electrical Worker Flow Chart. Training requirements: ES&H 114 (LOTO) / ES&H 375 (NFPA 70E) / ES&H 371 (electrical worker) - Observe Electrical Safe Work Practices. Refer to

386

Optimal Distributed Voltage Regulation in Power Distribution Networks  

E-Print Network (OSTI)

In this paper, we address the problem of voltage regulation in power distribution networks with deep-penetration of distributed energy resources (DERs), e.g., renewable-based generation, and storage-capable loads such as plug-in hybrid electric vehicles. We cast the problem as an optimization program, where the objective is to minimize the losses in the network subject to constraints on bus voltage magnitudes, limits on active and reactive power injections, transmission line thermal limits and losses. We provide sufficient conditions under which the optimization problem can be solved via its convex relaxation. Using data from existing networks, we show that the conditions are expected to be satisfied by most networks. We also provide an efficient distributed algorithm to solve the problem. The algorithm is asynchronous, with a communication topology that is the same as the electrical network topology. We illustrate the algorithm's performance in the IEEE 34-bus and the 123-bus feeder test systems.

Lam, Albert Y S; Dominguez-Garcia, Alejandro; Tse, David

2012-01-01T23:59:59.000Z

387

Analysis of Lightning-induced Voltages in Overhead Transmission Lines  

Science Journals Connector (OSTI)

Abstract In this work we study the coupling of lightning induced voltages in Overhead Transmission Lines .The study is led directly in the time domain with hold in account the effect of a finite conductivity of the soil. After discretization by the method so-called FDTD (Finite Difference Time Domain) of the lines equations excited by a lightning wave and the application in every node of the network in current and voltage, we deduct a equations system, of which the resolution permits us to deduct the induced electric quantities in every node of the network. In order to confirm our theoretical work, we present a set of applications that allows validating this study.

Mostefa. Boumaiza; Djamel. Labed

2014-01-01T23:59:59.000Z

388

Stabilized radio-frequency quadrupole  

DOE Patents (OSTI)

A long-vane stabilized radio frequency resonator for accelerating charged particles and including means defining a radio frequency resonator cavity, a plurality of long vanes mounted in the defining means for dividing the cavity into sections, and means interconnecting opposing ones of the plurality of vanes for stabilizing the resonator.

Lancaster, H.D.; Fugitt, J.A.; Howard, D.R.

1982-09-29T23:59:59.000Z

389

Distribution capacitor automation that controls voltage and saves energy  

SciTech Connect

The Electric Distribution Business Line of Southern California Edison Company (SCE) has begun a program to improve the distribution system operations and electrical efficiency. The program, called the Distribution System Efficiency Enhancement Program (DSEEP), consists of five principal projects: Automated Switching, Circuit Lock-Out Alarming, Substation Monitoring and Control, Outage Management, and Distribution Capacitor Automation Project (DCAP). DCAP is the largest and most sophisticated of the projects being implemented. The project takes advantage of fine-tuning customer voltages for conservation voltage regulation (CVR) benefits as well as minimizes line losses by reducing unnecessary reactive power flow. DCAP can also help to increase transmission line and substation capacity by improving system power factor. The DCAP system takes advantage of the distributed processing capability of meters, capacitor controllers, radios, and substation processors. DCAP uses two-way packet radios and new electronic meters that read real-time customer voltages as well as energy consumption. The radios transmit customer meter voltage information and capacitor status to substation processors, where a control algorithm runs to determine which capacitors should be turned on or off. The objective of DCAP is to reduce over-all net energy transfer from the substation to the customer and meet system VAR requirements. SCE has tested the system on 66 circuit capacitors (including 3 substation capacitors) on 18 circuits served from two substations. The positive results of the DCAP demonstrations has led to an aggressive roll-out plan for system-wide implementation of automating over 7600 switched capacitors by year-end 1995.

Williams, B.R.

1994-12-31T23:59:59.000Z

390

Analytical model for the radio-frequency sheath  

Science Journals Connector (OSTI)

A simple analytical model for the planar radio-frequency (rf) sheath in capacitive discharges is developed that is based on the assumptions of a step profile for the electron front, charge exchange collisions with constant cross sections, negligible ionization within the sheath, and negligible ion dynamics. The continuity, momentum conservation, and Poisson equations are combined in a single integro-differential equation for the square of the ion drift velocity, the so called sheath equation. Starting from the kinetic Boltzmann equation, special attention is paid to the derivation and the validity of the approximate fluid equation for momentum balance. The integrals in the sheath equation appear in the screening function which considers the relative contribution of the temporal mean of the electron density to the space charge in the sheath. It is shown that the screening function is quite insensitive to variations of the effective sheath parameters. The two parameters defining the solution are the ratios of the maximum sheath extension to the ion mean free path and the Debye length, respectively. A simple general analytic expression for the screening function is introduced. By means of this expression approximate analytical solutions are obtained for the collisionless as well as the highly collisional case that compare well with the exact numerical solution. A simple transition formula allows application to all degrees of collisionality. In addition, the solutions are used to calculate all static and dynamic quantities of the sheath, e.g., the ion density, fields, and currents. Further, the rf Child-Langmuir laws for the collisionless as well as the collisional case are derived. An essential part of the model is the a priori knowledge of the wave form of the sheath voltage. This wave form is derived on the basis of a cubic charge-voltage relation for individual sheaths, considering both sheaths and the self-consistent self-bias in a discharge with arbitrary symmetry. The externally applied rf voltage is assumed to be sinusoidal, although the model can be extended to arbitrary wave forms, e.g., for dual-frequency discharges. The model calculates explicitly the cubic correction parameter in the charge-voltage relation for the case of highly asymmetric discharges. It is shown that the cubic correction is generally moderate but more pronounced in the collisionless case. The analytical results are compared to experimental data from the literature obtained by laser electric field measurements of the mean and dynamic fields in the capacitive sheath for various gases and pressures. Very good agreement is found throughout.

Uwe Czarnetzki

2013-12-03T23:59:59.000Z

391

Real time voltage control using emergency demand response in distribution system by integrating advanced metering infrastructure  

Science Journals Connector (OSTI)

In this paper an analytical study is reported to demonstrate the effects of demand response on distribution network voltages profile. Also a new approach for real time voltage control is proposed which uses emergency demand response program aiming at maintaining voltage profile in an acceptable range with minimum cost. This approach will be active in emergency conditions where in real time the voltages in some nodes leave their permissible ranges. These emergency conditions are Distributed Generation (DG) units and lines outage and unpredictable demand and renewable generations' fluctuations. The proposed approach does not need the load and renewable generation forecast data to regulate voltage. To verify the effectiveness and robustness of the proposed control scheme the proposed voltage control scheme is tested on a typical distribution network. The simulation results show the effectiveness and capability of the proposed real time voltage control model to maintain smart distribution network voltage in specified ranges in both normal and emergency conditions.

Alireza Zakariazadeh; Shahram Jadid

2014-01-01T23:59:59.000Z

392

Demand Response by Decentralized Device Control Based on Voltage Level  

Science Journals Connector (OSTI)

This paper introduces a distributed, self-organizing approach to load control based on voltage measurement. A local voltage measurement defines a Level of Service (LoS), which is balanced with the neighboring ...

Wilfried Elmenreich; Stefan Schuster

2014-01-01T23:59:59.000Z

393

Demand Side Management using VOLTAGE / DISTRIBUTION OPTIMIZATION Quality improvement & Peak reduction  

Science Journals Connector (OSTI)

In order to improve the quality of the electrical energy delivered at consumer households a Voltage Optimization Device (VOD) is introduced in each household. This device controls the output voltage accurately at...

N. H. M. Hofmeester; C. J. van de Water

1994-01-01T23:59:59.000Z

394

E-Print Network 3.0 - ac voltage standard Sample Search Results  

NLE Websites -- All DOE Office Websites (Extended Search)

"volts, AC"), the "secondary" voltage is roughly 6 VAC. We shall use the "Universal Transformer... :" conversion of AC to DC You can use a diode to convert the AC voltage of the...

395

E-Print Network 3.0 - applied voltages ii Sample Search Results  

NLE Websites -- All DOE Office Websites (Extended Search)

dc-link voltage error is applied to the fun... --In this paper, a new hybrid active power filter topology is presented. A higher-voltage, low-switching fre... - quency...

396

Advanced Gate Drive for the SNS High Voltage Converter Modulator  

SciTech Connect

SLAC National Accelerator Laboratory is developing a next generation H-bridge switch plate [1], a critical component of the SNS High Voltage Converter Modulator [2]. As part of that effort, a new IGBT gate driver has been developed. The drivers are an integral part of the switch plate, which are essential to ensuring fault-tolerant, high-performance operation of the modulator. The redesigned driver improves upon the existing gate drive in several ways. The new gate driver has improved fault detection and suppression capabilities; suppression of shoot-through and over-voltage conditions, monitoring of dI/dt and Vce(sat) for fast over-current detection and suppression, and redundant power isolation are some of the added features. In addition, triggering insertion delay is reduced by a factor of four compared to the existing driver. This paper details the design and performance of the new IGBT gate driver. A simplified schematic and description of the construction are included. The operation of the fast over-current detection circuits, active IGBT over-voltage protection circuit, shoot-through prevention circuitry, and control power isolation breakdown detection circuit are discussed.

Nguyen, M.N.; Burkhart, C.; Kemp, M.A.; /SLAC; Anderson, D.E.; /Oak Ridge

2009-05-07T23:59:59.000Z

397

Linear inductive voltage adders (IVA) for advanced hydrodynamic radiography  

SciTech Connect

The electron beam which drifts through the multiple cavities of conventional induction linacs (LIA) is replaced in an IVA by a cylindrical metal conductor which extends along the entire length of the device and effectuates the addition of the accelerator cavity voltages. In the approach to radiography, the linear inductive voltage adder drives a magnetically immersed electron diode with a millimeter diameter cathode electrode and a planar anode/bremsstrahlung converter. Both anode and cathode electrodes are immersed in a strong (15--50 T) solenoidal magnetic field. The electron beam cross section is approximately of the same size as the cathode needle and generates a similar size, very intense x-ray beam when it strikes the anode converter. An IVA driven diode can produce electron beams of equal size and energy as a LIA but with much higher currents (40--50 kA versus 4--5 kA), simpler hardware and thus lower cost. The authors present here first experimental validations of the technology utilizing HERMES 3 and SABRE IVA accelerators. The electron beam voltage and current were respectively of the order of 10 MV and 40 kA. X-ray doses of up to 1 kR {at} 1 m and spot sizes as small as 1.7 mm (at 200 R doses) were measured.

Mazarakis, M.G.; Boyes, J.D.; Johnson, D.L. [and others

1998-09-01T23:59:59.000Z

398

Thermally-induced voltage alteration for integrated circuit analysis  

DOE Patents (OSTI)

A thermally-induced voltage alteration (TIVA) apparatus and method are disclosed for analyzing an integrated circuit (IC) either from a device side of the IC or through the IC substrate to locate any open-circuit or short-circuit defects therein. The TIVA apparatus uses constant-current biasing of the IC while scanning a focused laser beam over electrical conductors (i.e. a patterned metallization) in the IC to produce localized heating of the conductors. This localized heating produces a thermoelectric potential due to the Seebeck effect in any conductors with open-circuit defects and a resistance change in any conductors with short-circuit defects, both of which alter the power demand by the IC and thereby change the voltage of a source or power supply providing the constant-current biasing. By measuring the change in the supply voltage and the position of the focused and scanned laser beam over time, any open-circuit or short-circuit defects in the IC can be located and imaged. The TIVA apparatus can be formed in part from a scanning optical microscope, and has applications for qualification testing or failure analysis of ICs.

Cole, Jr., Edward I. (Albuquerque, NM)

2000-01-01T23:59:59.000Z

399

Fiber optic current monitor for high-voltage applications  

DOE Patents (OSTI)

A current monitor which derives its power from the conductor being measured for bidirectionally measuring the magnitude of current (from DC to above 50 khz) flowing through a conductor across which a relatively high level DC voltage is applied, includes a pair of identical transmitter modules connected in opposite polarity to one another in series with the conductor being monitored, for producing from one module a first light signal having an intensity directly proportional to the magnitude of current flowing in one direction through the conductor during one period of time, and from the other module a second light signal having an intensity directly proportional to the magnitude of current flowing in the opposite direction through the conductor during another period of time, and a receiver located in a safe area remote from the high voltage area for receiving the first and second light signals, and converting the same to first and second voltage signals having levels indicative of the magnitude of current being measured at a given time.

Renda, George F. (Plainsboro, NJ)

1992-01-01T23:59:59.000Z

400

Driving frequency effects on the characteristics of atmospheric pressure capacitive helium discharge  

SciTech Connect

Atmospheric pressure helium discharge characteristics were investigated for varying driving radio frequencies in the range between 1.86 and 27.1 MHz. As the driving frequency is raised, both gas breakdown and {alpha}-{gamma} transition voltages decrease due to the reduction in the electron drift loss. In addition, different discharge features such as normal, abnormal, {alpha}, and {gamma} modes show certain dependences on the frequency. Using a simple circuit model, the changes in sheath thickness from 2.35 to 0.11 mm, electron density from 0.26 to 15.6x10{sup 11} cm{sup -3} was obtained by raising the frequency from 1.86 to 27.1 MHz.

Moon, Se Youn; Kim, D. B.; Gweon, B.; Choe, W. [Department of Physics, Korea Advanced Institute of Science and Technology, 335 Gwahangno, Yuseong-gu, Daejeon 305-701 (Korea, Republic of)

2008-12-01T23:59:59.000Z

Note: This page contains sample records for the topic "frequency variable voltage" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


401

Battery energy storage system for frequency support in microgrids and with enhanced control features for uninterruptible supply of local loads  

Science Journals Connector (OSTI)

Abstract This paper proposes a battery energy storage system (BESS) to support the frequency control process within microgrids (MG) with high penetration of renewable energy sources (RES). The solution includes features that enhance the system’s stability and security of supply. The BESS can operate connected to MG or islanded and the transition between the two states is seamlessly coordinated by an original method. The BESS active power response is governed by an improved frequency controller on two layers, namely primary and secondary. It responds to frequency deviations by combining a conventional droop control method with a virtual inertia function to improve the system’s stability. The proposed BESS may also compensate the power of the local loads, so that the MG frequency transients can be reduced and, depending on the remaining inverter capacity, voltage support in the point of common coupling with the MG may be provided. If the MG power quality degrades in terms of the voltage and frequency, the BESS and the local load are disconnected from the MG and continue operating islanded. The BESS is reconnected to the MG after a smoothly resynchronization of the local voltage with the MG, without disturbing the local loads supply. Simulation and experimental results assesses the proposed control solutions.

I. Serban; C. Marinescu

2014-01-01T23:59:59.000Z

402

PHP: Constructs and Variables Introduction  

E-Print Network (OSTI)

PHP: Constructs and Variables Introduction This document describes: 1. the syntax and types of variables, 2. PHP control structures (i.e., conditionals and loops), 3. mixed-mode processing, 4. how to use one script from within another, 5. how to define and use functions, 6. global variables in PHP, 7

Vander Zanden, Brad

403

Accounting for spatially variable resolution in electrical resistivity tomography through field-scale rock-physics relations  

E-Print Network (OSTI)

Accounting for spatially variable resolution in electrical resistivity tomography through field of the voltages measured in an electrical resistivity tomography ERT survey produces maps of electrical resistivity, which can be used to infer changes in electrical properties, such as those caused

Singha, Kamini

404

An Open Question about Dependency of Life Time of Hardware Components and Dynamic Voltage Scaling  

E-Print Network (OSTI)

Open question about Dependency of Life Time of Hardware Components and Dynamic Voltage Scaling (A primary idea)

Jaberi, Nasrin

2012-01-01T23:59:59.000Z

405

Limiting discharge voltage of a capacitive energy store in a subway car  

Science Journals Connector (OSTI)

A method is proposed for calculating the limiting discharge voltage of a capacitive energy store in a subway car.

G. G. Ryabtsev; I. A. Ermakov

2012-12-01T23:59:59.000Z

406

Topology optimization-based distribution design of actuation voltage in static shape control of plates  

Science Journals Connector (OSTI)

This paper investigates the optimal spatial distribution of single-channel actuation voltage in static structural shape control problem. It is pointed out that single-channel actuation voltage input for shape control applications is of practical importance ... Keywords: Shape control, Single channel, Topology optimization, Voltage distribution

Zhan Kang; Liyong Tong

2008-10-01T23:59:59.000Z

407

Statistical Estimation of Leakage-Induced Power Grid Voltage Drop Considering Within-Die Process Variations  

E-Print Network (OSTI)

Statistical Estimation of Leakage-Induced Power Grid Voltage Drop Considering Within-Die Process the power grid, the grid develops large voltage drops, which is an unavoidable background level of noise on the grid. We develop techniques for estimation of the statistics of the leakage-induced power grid voltage

Najm, Farid N.

408

Statistical Estimation of LeakageInduced Power Grid Voltage Drop Considering WithinDie Process Variations #  

E-Print Network (OSTI)

Statistical Estimation of Leakage­Induced Power Grid Voltage Drop Considering Within­Die Process the power grid, the grid develops large voltage drops, which is an unavoidable background level of noise on the grid. We develop techniques for estimation of the statistics of the leakage­induced power grid voltage

Najm, Farid N.

409

Statistical Estimation of Circuit Timing Vulnerability Due to Leakage-Induced Power Grid Voltage Drop  

E-Print Network (OSTI)

Statistical Estimation of Circuit Timing Vulnerability Due to Leakage-Induced Power Grid Voltage voltage drops on the power grid that can affect circuit timing. We propose a statistical analysis supply voltage to circuit devices is referred to as the power grid. The consequences of power grid

Najm, Farid N.

410

Low-Voltage Ride-Through Techniques for DFIG-Based Wind Turbines  

E-Print Network (OSTI)

Low-Voltage Ride-Through Techniques for DFIG-Based Wind Turbines: State-of-the-Art Review deals with low-voltage ride-through (LVRT) capability of wind turbines (WTs) and in particular those as to index some emerging solutions. Index Terms--Wind turbine, doubly-fed induction generator, low voltage

Paris-Sud XI, Université de

411

Research on fuzzy logic based dynamic boundary voltage and reactive power integrated control method  

Science Journals Connector (OSTI)

Aiming at the existing problems of conventional substation voltage and reactive power integrated control method, a new fuzzy logic based dynamic reactive power boundary voltage and reactive power integrated control method is proposed. Fuzzy logic control ... Keywords: dynamic boundary, fuzzy logic, reactive power, voltage

Zigang Xu; Fei Wang

2009-06-01T23:59:59.000Z

412

DSP IMPLEMENTATION OF DC VOLTAGE REGULATION USING ADAPTIVE CONTROL FOR 200 KW 62000 RPM  

E-Print Network (OSTI)

to control the DC voltage for 200 kW induction generator rated at a speed of 62000 RPM under different load to regulate the DC voltage for high speed induction generators rated from 5 kW to 200 kW. ii #12DSP IMPLEMENTATION OF DC VOLTAGE REGULATION USING ADAPTIVE CONTROL FOR 200 KW 62000 RPM INDUCTION

Wu, Thomas

413

An Approximate Dynamic Programming Algorithm for the Allocation of High-Voltage Transformer Spares in the  

E-Print Network (OSTI)

An Approximate Dynamic Programming Algorithm for the Allocation of High-Voltage Transformer Spares high-voltage transformer spares throughout the electric grid to mitigate the risk of random transformer-voltage transformers are an integral part of the electric transmission system. A catas- trophic transformer failure

Powell, Warren B.

414

Application-Directed Voltage Scaling Johan Pouwelse, Koen Langendoen, and Henk Sips  

E-Print Network (OSTI)

--Clock (and voltage) scheduling is an important tech- nique to reduce the energy consumption of processors that sup- port voltage scaling. It is difficult, however, to achieve good re- sults using only statistics to the scheduler control- ling the clock speed and processor voltage. This paper describes our Energy Priority

Pouwelse, Johan

415

Performance Analysis of a Hybrid Asymmetric Multilevel Inverter for High Voltage Active Power Filter Applications  

E-Print Network (OSTI)

Performance Analysis of a Hybrid Asymmetric Multilevel Inverter for High Voltage Active Power voltage-source inverters connected in series (known as cascaded hybrid asymmetric multilevel inverter voltage application due to semiconductor constraint. In order to achieve higher power level, hybrid

Catholic University of Chile (Universidad CatĂłlica de Chile)

416

Effect of the change in the load resistance on the high voltage pulse transformer of the intense electron-beam accelerators  

SciTech Connect

A high voltage pulse transformer (HVPT) is usually used as a charging device for the pulse forming line (PFL) of intense electron-beam accelerators (IEBAs). Insulation of the HVPT is one of the important factors that restrict the development of the HVPT. Until now, considerable effort has been focused on minimizing high field regions to avoid insulation breakdown between windings. Characteristics of the HVPT have been widely discussed to achieve these goals, but the effects of the PFL and load resistance on HVPT are usually neglected. In this paper, a HVPT is used as a charging device for the PFL of an IEBA and the effect of the change in the load resistance on the HVPT of the IEBA is presented. When the load resistance does not match the wave impedance of the PFL, a high-frequency bipolar oscillating voltage will occur, and the amplitude of the oscillating voltage will increase with the decrease in the load resistance. The load resistance approximates to zero and the amplitude of the oscillating voltage is much higher. This makes it easier for surface flashover along the insulation materials to form and decrease the lifetime of the HVPT.

Cheng Xinbing; Liu Jinliang; Qian Baoliang; Zhang Yu; Zhang Hongbo [College of Photoelectrical Science and Engineering, National University of Defense Technology, Hunan 410073 (China)

2009-11-15T23:59:59.000Z

417

Microwave and Radio Frequency Workshop  

Energy.gov (U.S. Department of Energy (DOE))

At the Microwave and Radio Frequency Workshop (held in Long Beach, CA, on July 25, 2012), academic and industry experts discussed the existing and emerging electrotechnologies – such as microwave ...

418

AUTO ID FUTURE - FREQUENCY AGNOSTIC  

E-Print Network (OSTI)

Identification of information is one key to the development of intelligent decision systems of the future. Frequency agnostic automatic identification is only one step in the physical world to make physical objects identify ...

DATTA, SHOUMEN

419

Frequency regulator for synchronous generators  

DOE Patents (OSTI)

The present invention is directed to a novel frequency regulator which controls a generator output frequency for variations in both the input power to the generator and the power supplied to an uncontrolled external load. The present invention further includes over current and current balance protection devices which are relatively inexpensive to manufacture, which may be encapsulated to provide protection from the operating environment and which respond more quickly than previously known electromechanical devices.

Karlicek, Robert F. (1920 Camino Centroloma, Fullerton, CA 92633)

1982-01-01T23:59:59.000Z

420

Frequency regulator for synchronous generators  

DOE Patents (OSTI)

The present invention is directed to a novel frequency regulator which controls a generator output frequency for variations in both the input power to the generator and the power supplied to an uncontrolled external load. The present invention further includes over current and current balance protection devices which are relatively inexpensive to manufacture, which may be encapsulated to provide protection from the operating environment and which respond more quickly than previously known electromechanical devices. 11 figs.

Karlicek, R.F.

1982-08-10T23:59:59.000Z

Note: This page contains sample records for the topic "frequency variable voltage" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


421

The Application of Droop-Control in Distributed Energy Resources to Extend the Voltage Collapse Margin  

SciTech Connect

The growth in distributed energy resources has the potential to reduce system stresses caused by transmission grid congestion by supplying power and voltage regulation closer to load centers. However, the additional voltage regulation provided by these resources can mask the onset of voltage collapse. Local voltage support flattens the slope in the upper region of the power-voltage nose curve. Coordinating voltage-regulation behavior with the droop-control scheme in distributed resources improves the observation of voltage collapse margins. Incorporating distributed resource models in the continuation power flow analysis, allows the exploration of the power transfer gains by the application of distributed resources. The analysis provides insight to the impact of droop control on the behavior of the power-voltage curve and voltage collapse. The analysis is applied to a fixed speed induction generator wind farm with separate reactive compensation and the interconnection to the local power system. Results reveal that coordinating the droop control strategy allows the distributed resource to significantly increase the voltage collapse margin without hiding the threat of voltage stability problems.

Henry, Shawn D. [Florida State University; Rizy, D Tom [ORNL; Baldwin, Thomas L [Florida State University; Kueck, John D [ORNL; Li, Fangxing [ORNL

2008-01-01T23:59:59.000Z

422

Frequencies of Tetramer+ T Cells Specific for the Wild-Type Sequence p53264–272 Peptide in the Circulation of Patients with Head and Neck Cancer  

Science Journals Connector (OSTI)

...loglinear models to the frequencies of each variable in the 3 2 2 contingency...determined that the frequency of p53264-272-specific...of CTL, which might drive the selection of epitope-loss...mutations and a low frequency of wt p53-specific...

Thomas K. Hoffmann; Albert D. Donnenberg; Sydney D. Finkelstein; Vera S. Donnenberg; Ulrike Friebe-Hoffmann; Eugene N. Myers; Ettore Appella; Albert B. DeLeo; and Theresa L. Whiteside

2002-06-15T23:59:59.000Z

423

High frequency of K-ras codon 12 mutations in bronchoalveolar lavage fluid of patients at high risk for second primary lung cancer.  

Science Journals Connector (OSTI)

...lung cancer. | A high frequency of K-ras mutations...Cancer Research 479 High Frequency of K-ras Codon 12...ABSTRACT A high frequency of K-ras mutations...9610 Medical Center Drive, Rockville, MD 20850...specimens. Only a small, variable percent-age of bronchial...

F M Scott; R Modali; T A Lehman; M Seddon; K Kelly; E C Dempsey; V Wilson; M S Tockman; and J L Mulshine

1997-03-01T23:59:59.000Z

424

Radio-frequency plasma transducer for use in harsh environments  

SciTech Connect

We describe a compact transducer used to generate and modulate low-intensity radio-frequency atmospheric pressure plasma (RF-APP) for high temperature gap measurement and generation of air-coupled ultrasound. The new transducer consists of a quarter-wave transmission line where the ground return path is a coaxial solenoid winding. The RF-APP is initiated at the open end of the transmission line and stabilized by passive negative feedback between the electrical impedance of the plasma and the energy stored in the solenoid. The electrical impedance of the plasma was measured at the lower-voltage source end of the transducer, eliminating the need to measure kilovolt-level voltages near the discharge. We describe the use of a 7 MHz RF-APP prototype as a harsh-environment clearance sensor to demonstrate the suitability of plasma discharges for a common nondestructive inspection application. Clearance measurements of 0-5 mm were performed on a rotating calibration target with a measurement precision of 0.1 mm and a 20 kHz sampling rate.

May, Andrew; Andarawis, Emad [GE Global Research, 1 Research Circle, Niskayuna, New York 12309 (United States)

2007-10-15T23:59:59.000Z

425

Radio-frequency plasma transducer for use in harsh environments  

Science Journals Connector (OSTI)

We describe a compact transducer used to generate and modulate low-intensity radio-frequency atmospheric pressure plasma (RF-APP) for high temperature gap measurement and generation of air-coupled ultrasound. The new transducer consists of a quarter-wave transmission line where the ground return path is a coaxial solenoid winding. The RF-APP is initiated at the open end of the transmission line and stabilized by passive negative feedback between the electrical impedance of the plasma and the energy stored in the solenoid. The electrical impedance of the plasma was measured at the lower-voltage source end of the transducer eliminating the need to measure kilovolt-level voltages near the discharge. We describe the use of a 7 MHz RF-APP prototype as a harsh-environment clearance sensor to demonstrate the suitability of plasma discharges for a common nondestructive inspection application. Clearance measurements of 0 – 5 mm were performed on a rotating calibration target with a measurement precision of 0.1 mm and a 20 kHz sampling rate.

Andrew May; Emad Andarawis

2007-01-01T23:59:59.000Z

426

Outdoor PV Module Degradation of Current-Voltage Parameters: Preprint  

SciTech Connect

Photovoltaic (PV) module degradation rate analysis quantifies the loss of PV power output over time and is useful for estimating the impact of degradation on the cost of energy. An understanding of the degradation of all current-voltage (I-V) parameters helps to determine the cause of the degradation and also gives useful information for the design of the system. This study reports on data collected from 12 distinct mono- and poly-crystalline modules deployed at the National Renewable Energy Laboratory (NREL) in Golden, Colorado. Most modules investigated showed < 0.5%/year decrease in maximum power due to short-circuit current decline.

Smith, R. M.; Jordan, D. C.; Kurtz, S. R.

2012-04-01T23:59:59.000Z

427

Self-monitoring high voltage transmission line suspension insulator  

DOE Patents (OSTI)

A high voltage transmission line suspension insulator (18 or 22) which monitors its own dielectric integrity. A dielectric rod (10) has one larger diameter end fitting attachable to a transmission line and another larger diameter end fitting attachable to a support tower. The rod is enclosed in a dielectric tube (14) which is hermetically sealed to the rod's end fittings such that a liquidtight space (20) is formed between the rod and the tube. A pressurized dielectric liquid is placed within that space. A discoloring dye placed within this space is used to detect the loss of the pressurized liquid.

Stemler, Gary E. (Vancouver, WA); Scott, Donald N. (Vancouver, WA)

1981-01-01T23:59:59.000Z

428

Voltage sensor with fiber Fabry-Perot interferometer  

E-Print Network (OSTI)

with smaller strain constants, a larger voltage must be applied to get a 2x round trip phase shift. Hence, a longer FFPI is needed to get higher resolution. 16 A plate type PZT was selected because it's more convenient to attach to a thermo-electric cooler... in electron-beam evaporation system, they can be spliced to uncoated fibers, which also have cleaved end surfaces. The basic configuration for this Siecor Model M 67 fusion splicer is shown in fig. 12. A electric arc is initiated between the electrodes...

Wann, Been-Huey

1992-01-01T23:59:59.000Z

429

Light-weight DC to very high voltage DC converter  

DOE Patents (OSTI)

A DC-DC converter capable of generating outputs of 100 KV without a transformer comprises a silicon opening switch (SOS) diode connected to allow a charging current from a capacitor to flow into an inductor. When a specified amount of charge has flowed through the SOS diode, it opens up abruptly; and the consequential collapsing field of the inductor causes a voltage and current reversal that is steered into a load capacitor by an output diode. A switch across the series combination of the capacitor, inductor, and SOS diode closes to periodically reset the SOS diode by inducing a forward-biased current.

Druce, Robert L. (Union City, CA); Kirbie, Hugh C. (Dublin, CA); Newton, Mark A. (Livermore, CA)

1998-01-01T23:59:59.000Z

430

Light-weight DC to very high voltage DC converter  

DOE Patents (OSTI)

A DC-DC converter capable of generating outputs of 100 KV without a transformer comprises a silicon opening switch (SOS) diode connected to allow a charging current from a capacitor to flow into an inductor. When a specified amount of charge has flowed through the SOS diode, it opens up abruptly; and the consequential collapsing field of the inductor causes a voltage and current reversal that is steered into a load capacitor by an output diode. A switch across the series combination of the capacitor, inductor, and SOS diode closes to periodically reset the SOS diode by inducing a forward-biased current. 1 fig.

Druce, R.L.; Kirbie, H.C.; Newton, M.A.

1998-06-30T23:59:59.000Z

431

Photonic Radio-Frequency Phase Detector based on Radio-Frequency to Intermediate-Frequency Phase Mapping  

Science Journals Connector (OSTI)

A photonic radio-frequency phase detector based on radio-frequency (RF) to intermediate-frequency mapping is demonstrated, and the theoretical principle of the design is explained.

Sun, Dongning; Dong, Yi; Wang, Siwei; Xia, Zongyang; Xie, Weilin; Shi, Hongxiao; Yi, Lilin; Hu, Weisheng

432

Monitoring variability of multivariate processes  

Science Journals Connector (OSTI)

The paper focuses on determining changes in process variability of multivariate processes. The problem is compounded by the fact that any of the elements in the variance-covariance matrix of variables could change, leading to a change in the process variability. While it may not be feasible to maintain individual control charts for each element of the variance-covariance matrix, some aggregate measure of the variability criteria could be monitored to initially determine if a change has occurred in the process variability. A couple of aggregate measures are proposed and the performance of these suggested measures is explored through a simulation procedure. Compared to the traditional method, which monitors the determinant of the variance-covariance matrix, these alternatives perform well. The performance measure used is the mean time to first detection of a change in the process variability.

Amitava Mitra; Mark Clark

2014-01-01T23:59:59.000Z

433

Methods, systems and apparatus for controlling third harmonic voltage when operating a multi-space machine in an overmodulation region  

SciTech Connect

Methods, system and apparatus are provided for controlling third harmonic voltages when operating a multi-phase machine in an overmodulation region. The multi-phase machine can be, for example, a five-phase machine in a vector controlled motor drive system that includes a five-phase PWM controlled inverter module that drives the five-phase machine. Techniques for overmodulating a reference voltage vector are provided. For example, when the reference voltage vector is determined to be within the overmodulation region, an angle of the reference voltage vector can be modified to generate a reference voltage overmodulation control angle, and a magnitude of the reference voltage vector can be modified, based on the reference voltage overmodulation control angle, to generate a modified magnitude of the reference voltage vector. By modifying the reference voltage vector, voltage command signals that control a five-phase inverter module can be optimized to increase output voltages generated by the five-phase inverter module.

Perisic, Milun; Kinoshita, Michael H; Ranson, Ray M; Gallegos-Lopez, Gabriel

2014-06-03T23:59:59.000Z

434

An ultra-capacitor for frequency stability enhancement in small-isolated power systems: Models, simulation and field tests  

Science Journals Connector (OSTI)

Abstract The most relevant issue in operation of isolated power systems is frequency stability. Frequency stability is concerned with the ability of generators to supply the loads at an acceptable frequency after a disturbance. Frequency stability is governed by the kinetic energy stored in the generator-prime mover rotating masses and the prime mover frequency primary regulation. If frequency excursions are not within +/?2.5 Hz range, cascade tripping of the remaining generators can occur because of generator over/under frequency protections tripping. Energy storage systems can contribute to frequency stability enhancement if their discharging is governed by a frequency controller. Endesa is leading a research project on testing the state of the art of energy storage systems for several applications (peak-shaving, voltage control, frequency control) in several isolated power systems of the Canary Islands. Several applications are being investigated. One of them consists on the application of a 4 MW–5 s ultracapacitor (UC) for frequency stability enhancement of the La Palma power system. This paper reports the dynamic model developed for time domain simulation and controller design of frequency stability, and field tests undertaken to validate models and the controller settings. A simple but still accurate model is presented. The proposed model takes into account the UC’s state of charge (SoC) and it represents the dynamics of the power electronics by means of a non-linear first-order model. The frequency control consists of droop control and inertia emulation. Ramp rate limits, power limits and SoC are also taken into account in the frequency control. In comparison with the recorded field tests, the proposed model is able to accurately represent the response of the UC for the purpose of frequency stability analysis.

I. Egido; L. Sigrist; E. Lobato; L. Rouco; A. Barrado

2015-01-01T23:59:59.000Z

435

Bi-directional power control system for voltage converter  

DOE Patents (OSTI)

A control system for a voltage converter includes: a power comparator for comparing a power signal on input terminals of the converter with a commanded power signal and producing a power comparison signal; a power regulator for transforming the power comparison signal to a commanded current signal; a current comparator for comparing the commanded current signal with a measured current signal on output terminals of the converter and producing a current comparison signal; a current regulator for transforming the current comparison signal to a pulse width modulator (PWM) duty cycle command signal; and a PWM for using the PWM duty cycle command signal to control electrical switches of the converter. The control system may further include: a command multiplier for converting a voltage signal across the output terminals of the converter to a gain signal having a value between zero (0) and unity (1), and a power multiplier for multiplying the commanded power signal by the gain signal to provide a limited commanded power signal, wherein power comparator compares the limited commanded power signal with the power signal on the input terminals.

Garrigan, Neil Richard (Niskayuna, NY); King, Robert Dean (Schenectady, NY); Schwartz, James Edward (Slingerlands, NY)

1999-01-01T23:59:59.000Z

436

JOURNAL OF STRUCTURAL ENGINEERING / MAY 2001 / 527 APPARENT PERIODS OF A BUILDING. II: TIME-FREQUENCY ANALYSIS  

E-Print Network (OSTI)

of a two-part paper, the analysis of the apparent frequency of a seven-story reinforced-concrete hotel. The results also suggest ``self healing'' believed to result from settlement of the soil with time and dynamic compaction from aftershock shaking. Implications of such high variability of the system frequency

Southern California, University of

437

Estimation of changes in energy consumption for heat supply due to interannual temperature variability in the south of the Ukraine  

Science Journals Connector (OSTI)

The influence of low-frequency variability of average over the heating season air temperature on population demands in heat supply is considered. Based on monthly mean temperature values for the period from 18...

A. Kh. Degterev; L. N. Degtereva

2008-11-01T23:59:59.000Z

438

Temperature dependent junction capacitance-voltage characteristics of Ni embedded TiN/SiO{sub 2}/p-Si metal–insulator–semiconductor structure  

SciTech Connect

This work presents the junction capacitance–voltage characteristics of highly textured/epitaxial Ni nanoparticle embedded in TiN matrix (TiN(Ni)) metal-insulator-semiconductor TiN(Ni)/SiO{sub 2}/p-Si (100) heterojunction in the temperature range of 10–300?K. This heterojunction behaves as metal-semiconductor junction with unavoidable leakage through native oxide SiO{sub 2} layer. The clockwise hysteresis loop has been observed in the capacitance-voltage characteristics measured at various frequencies mainly due to presence of trap centers at the TiN(Ni)/SiO{sub 2} interface and these are temperature dependent. The spin-dependent trap charge effect at the interface influences the quadratic nature of the capacitance with magnetic field. The junction magnetocapacitance (JMC) is observed to be dependent on both temperature and frequency. The highest JMC of this heterojunction has been observed at 200?K at higher frequencies (100?kHz–1?MHz). It is found that there is not much effect of band structure modification under magnetic field causing the JMC.

Panda, J.; Nath, T. K., E-mail: tnath@phy.iitkgp.ernet.in [Department of Physics and Meteorology, Indian Institute of Technology Kharagpur, Kharagpur, West Bengal 721302 (India); Chattopadhyay, S. [Department of Physics and Meteorology, Indian Institute of Technology Kharagpur, Kharagpur, West Bengal 721302 (India); Amity Institute of Nano Technology, Amity University, Sector-125, Noida, Uttar Pradesh 201313 (India)

2013-12-14T23:59:59.000Z

439

High-frequency resonances in photorefractive crystals  

Science Journals Connector (OSTI)

Two-wave mixing in photorefractive materials is investigated for the case of applied dc electric fields and large detuning frequencies and for high-frequency alternating electric...

Grunnet-Jepsen, A; Aubrecht, I; Solymar, L

1995-01-01T23:59:59.000Z

440

Sum Frequency Generation for Surface Vibrational Spectroscopy...  

NLE Websites -- All DOE Office Websites (Extended Search)

Sum Frequency Generation for Surface Vibrational Spectroscopy Sum Frequency Generation for Surface Vibrational Spectroscopy This customized SFG-VS spectrometer incorporates unique...

Note: This page contains sample records for the topic "frequency variable voltage" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


441

Selection automatique de variables pertinentes  

E-Print Network (OSTI)

S´election automatique de variables pertinentes Vers la d´ecouverte de nouvelles modalit´es sensori-motrices corr´elations entre ses variables sensori-motrices afin d'apprendre `a r´esoudre sa t^ache d

Boyer, Edmond

442

Heart Rate Variability Analysis Using Threshold of Wavelet Package Coefficients  

E-Print Network (OSTI)

In this paper, a new efficient feature extraction method based on the adaptive threshold of wavelet package coefficients is presented. This paper especially deals with the assessment of autonomic nervous system using the background variation of the signal Heart Rate Variability HRV extracted from the wavelet package coefficients. The application of a wavelet package transform allows us to obtain a time-frequency representation of the signal, which provides better insight in the frequency distribution of the signal with time. A 6 level decomposition of HRV was achieved with db4 as mother wavelet, and the above two bands LF and HF were combined in 12 specialized frequencies sub-bands obtained in wavelet package transform. Features extracted from these coefficients can efficiently represent the characteristics of the original signal. ANOVA statistical test is used for the evaluation of proposed algorithm.

Kheder, G; Massoued, M Ben; Samet, M

2009-01-01T23:59:59.000Z

443

Retarding field analyzer for ion energy distribution measurements at a radio-frequency biased electrode  

SciTech Connect

A retarding field energy analyzer designed to measure ion energy distributions impacting a radio-frequency biased electrode in a plasma discharge is examined. The analyzer is compact so that the need for differential pumping is avoided. The analyzer is designed to sit on the electrode surface, in place of the substrate, and the signal cables are fed out through the reactor side port. This prevents the need for modifications to the rf electrode--as is normally the case for analyzers built into such electrodes. The capabilities of the analyzer are demonstrated through experiments with various electrode bias conditions in an inductively coupled plasma reactor. The electrode is initially grounded and the measured distributions are validated with the Langmuir probe measurements of the plasma potential. Ion energy distributions are then given for various rf bias voltage levels, discharge pressures, rf bias frequencies - 500 kHz to 30 MHz, and rf bias waveforms - sinusoidal, square, and dual frequency.

Gahan, D.; Hopkins, M. B. [National Centre for Plasma Science and Technology, Dublin City University, Glasnevin, Dublin 9 (Ireland); Dolinaj, B. [Impedans Ltd., Invent Centre, Dublin City University, Glasnevin, Dublin 9 (Ireland)

2008-03-15T23:59:59.000Z

444

Tunable metamaterials based on voltage controlled strong coupling  

SciTech Connect

We present the design, fabrication, and realization of an electrically tunable metamaterial operating in the mid-infrared spectral range. Our devices combine intersubband transitions in semiconductor quantum-wells with planar metamaterials and operate in the strong light-matter coupling regime. The resonance frequency of the intersubband transition can be controlled by an external bias relative to the fixed metamaterial resonance. This allows us to switch dynamically from an uncoupled to a strongly coupled system and thereby to shift the eigenfrequency of the upper polariton branch by 2.5 THz (corresponding to 8% of the center frequency or one full linewidth) with a bias of 5?V.

Benz, Alexander, E-mail: anbenz@sandia.gov; Brener, Igal [Center for Integrated Nanotechnologies (CINT), Sandia National Laboratories, P.O. Box 5800, Albuquerque, New Mexico 87185 (United States) [Center for Integrated Nanotechnologies (CINT), Sandia National Laboratories, P.O. Box 5800, Albuquerque, New Mexico 87185 (United States); Sandia National Laboratories, P.O. Box 5800, Albuquerque, New Mexico 87185 (United States); Montańo, Inčs; Klem, John F. [Sandia National Laboratories, P.O. Box 5800, Albuquerque, New Mexico 87185 (United States)] [Sandia National Laboratories, P.O. Box 5800, Albuquerque, New Mexico 87185 (United States)

2013-12-23T23:59:59.000Z

445

LM139/LM239/LM339/LM2901/LM3302 Low Power Low Offset Voltage Quad Comparators  

E-Print Network (OSTI)

LM139/LM239/LM339/LM2901/LM3302 Low Power Low Offset Voltage Quad Comparators General Description The LM139 series consists of four independent precision voltage comparators with an offset voltage clock timers; multivibrators and high voltage digital logic gates. The LM139 series was designed

Lanterman, Aaron

446

Voltage/Pitch Control for Maximization and Regulation of Active/Reactive Powers in Wind Turbines with Uncertainties  

E-Print Network (OSTI)

This paper addresses the problem of controlling a variable-speed wind turbine with a Doubly Fed Induction Generator (DFIG), modeled as an electromechanically-coupled nonlinear system with rotor voltages and blade pitch angle as its inputs, active and reactive powers as its outputs, and most of the aerodynamic and mechanical parameters as its uncertainties. Using a blend of linear and nonlinear control strategies (including feedback linearization, pole placement, uncertainty estimation, and gradient-based potential function minimization) as well as time-scale separation in the dynamics, we develop a controller that is capable of maximizing the active power in the Maximum Power Tracking (MPT) mode, regulating the active power in the Power Regulation (PR) mode, seamlessly switching between the two modes, and simultaneously adjusting the reactive power to achieve a desired power factor. The controller consists of four cascaded components, uses realistic feedback signals, and operates without knowledge of the C_p-...

Guo, Yi; Jiang, John N; Tang, Choon Yik; Ramakumar, Rama G

2010-01-01T23:59:59.000Z

447

Time Variability of the "Quiet" Sun Observed  

Science Journals Connector (OSTI)

The Transition Region and Coronal Explorer (TRACE) observed a "quiet-Sun" region on 1999 February 17 from 02:15 UT to 3:00 UT with full resolution (05 pixel size), high cadence (125 s), and deep exposures (65 and 46 s) in the 171 Ĺ and 195 Ĺ wavelengths. We start our investigation of the time variability of "quiet-Sun" images with a detailed analysis of instrumental and nonsolar effects, such as orbital temperature variations, filtering of particle radiation spikes, spacecraft pointing drift, and solar rotation tracking. We quantify the magnitude of various noise components (photon Poisson statistics, data digitization, data compression, and readout noise) and establish an upper limit for the data noise level, above which temporal variability can safely be attributed to solar origin. We develop a pattern recognition code that extracts spatiotemporal events with significant variability, yielding a total of 3131 events in 171 Ĺ and 904 events in 195 Ĺ. We classify all 904 events detected in 195 Ĺ according to flarelike characteristics and establish a numerical flare criterion based on temporal, spatial, and dynamic cross-correlation coefficients between the two observed temperatures (0.9 and 1.4 MK). This numerical criterion matches the visual flare classification in 83% of the cases and can be used for automated flare search. Using this flare discrimination criterion we find that only 35% (and 25%) of the events detected in 171 (and 195) Ĺ represent flarelike events. The discrimination of flare events leads to a frequency distribution of peak fluxes, N(?F) ? ?F-1.83±0.07 at 195 Ĺ, which is significantly flatter than the distribution of all events. A sensitive discrimination criterion of flare events is therefore important for microflare statistics and for conclusions on their occurrence rate and efficiency for coronal heating.

Markus J. Aschwanden; Richard W. Nightingale; Ted D. Tarbell; C. J. Wolfson

2000-01-01T23:59:59.000Z

448

Seasonal frequency of ciguatoxic barracuda in southwest Puerto Rico  

Science Journals Connector (OSTI)

Ciguatoxicity of barracuda (Sphyraena barracuda) head, viscera and flesh tissues has been determined in 219 specimens caught along the southwest coast of Puerto Rico from March 1985 through May 1987. Twenty-nine percent of these specimens were toxic. Monthly frequencies of ciguatoxic barracuda showed an apparent seasonal variability, with peak values (60–70% toxic fish) in the late winter-early spring (January–May) and fall (August–November). Minimal frequencies (0–10% toxic fish) were observed during June–July and December. The most frequently toxic tissues in poisonous animals were the viscera and head. Viscera tissue was the only toxic tissue found in 31% of the posionous fish assayed, and this tissue was poisonous in all toxic fish. In no case was a poisonous specimen found to have toxic flesh alone. Marked temporal variation in frequency of ciguatoxicity suggests that ciguatera toxins, at least in their active form, are not accumulated in barracuda tissues for extended periods of time. Variability in barracuda ciguatoxicity may reflect fluctuations in the toxicity of smaller reef fish prey, seasonal fluctuations in toxic benthic dinoflagellates and/or changes in the ability of the barracuda to detoxify ingested poisons or their precursors.

T.R. Tosteson; D.L. Ballantine; H.D. Durst

1988-01-01T23:59:59.000Z

449

Local Voltage Support from Distributed Energy Resources to Prevent Air Conditioner Motor Stalling  

SciTech Connect

Microgrid voltage collapse often happens when there is a high percentage of low inertia air-conditioning (AC) motors in the power systems. The stalling of the AC motors results in Fault Induced Delayed Voltage Recovery (FIDVR). A hybrid load model including typical building loads, AC motor loads, and other induction motor loads is built to simulate the motoring stalling phenomena. Furthermore, distributed energy resources (DE) with local voltage support capability are utilized to boost the local bus voltage during a fault, and prevent the motor stalling. The simulation results are presented. The analysis of the simulation results show that local voltage support from multiple DEs can effectively and economically solve the microgrid voltage collapse problem.

Baone, Chaitanya A [ORNL] [ORNL; Xu, Yan [ORNL] [ORNL; Kueck, John D [ORNL] [ORNL

2010-01-01T23:59:59.000Z

450

Bright and fast voltage reporters across the visible spectrum via electrochromic FRET (eFRET)  

E-Print Network (OSTI)

We present a palette of brightly fluorescent genetically encoded voltage indicators (GEVIs) with excitation and emission peaks spanning the visible spectrum, sensitivities from 6 - 10% Delta F/F per 100 mV, and half-maximal response times from 1 - 7 ms. A fluorescent protein is fused to an Archaerhodopsin-derived voltage sensor. Voltage-induced shifts in the absorption spectrum of the rhodopsin lead to voltage-dependent nonradiative quenching of the appended fluorescent protein. Through a library screen, we identified linkers and fluorescent protein combinations which reported neuronal action potentials in cultured rat hippocampal neurons with a single-trial signal-to-noise ratio from 6.6 to 11.6 in a 1 kHz imaging bandwidth at modest illumination intensity. The freedom to choose a voltage indicator from an array of colors facilitates multicolor voltage imaging, as well as combination with other optical reporters and optogenetic actuators.

Zou, Peng; Douglass, Adam D; Hochbaum, Daniel R; Brinks, Daan; Werley, Christopher A; Harrison, D Jed; Campbell, Robert E; Cohen, Adam E

2014-01-01T23:59:59.000Z

451

Intelligent Radio Frequency (RF) Monitoring  

E-Print Network (OSTI)

? Intelligent Radio Frequency (RF) Monitoring ? 2009 Armstrong International, Inc. www.armstronginternational.com 2 ?Expect many enjoyable experiences!? David M. Armstrong Present Process Challenges ? Identifying a failure ? Procedure.... Armstrong Steam Trap Challenges ? Identifying a failure ? Manpower ? Location ? Magnitude of failure ? Energy loss ? Loss of heat transfer ? Justification for repair ? ?Speed of Implementation? ? Environmental concerns Manpower Location 4...

Kimbrough, B.

452

Seismic vulnerability assessment of a high voltage disconnect switch  

Science Journals Connector (OSTI)

Abstract This paper deals with the seismic vulnerability of high voltage equipment typically installed in electric substations. In particular, the seismic response of a 380 kV vertical disconnect switch has been investigated based on the results of an experimental campaign carried out at Roma Tre University. According to a series of non-linear analyses, the influence of the most significant parameters on the seismic behavior of this apparatus has been analyzed and the corresponding fragility curves have been evaluated by using the Effective Fragility Analysis method. The results showed a limited vulnerability of the disconnect switch, whose most critical parts are the bottom joint of the ceramic support column and the steel column base.

Fabrizio Paolacci; Renato Giannini; Silvia Alessandri; Gianmarco De Felice

2014-01-01T23:59:59.000Z

453

Discriminator based on voltage comparator for nuclear physics research  

SciTech Connect

This paper describes a simple discriminator of low-level pulses with integral discrimination based on a K521SA3 comparator. The discriminator can be used to record pulses with durations of greater than or equal to 0.1 usec and amplitudes of greater than or equal to 1 mV. the input-pulse amplitude must not exceed the supply-voltage amplitude. A schematic diagram of the discriminator is given. For operation of the NGR spectrometer in the constant-velocity mode, the comparator was gated by the bipolar vibrator-velocity signal. The described circuit is reliable under laboratory conditions and its use is promising in multi-input systems such as those with multisection coordinate detectors.

Vorob'ev, V.A.; Kiselev, A.A.; Kuz'min, R.N.

1985-12-01T23:59:59.000Z

454

Effect of DC voltage pulses on memristor behavior.  

SciTech Connect

Current knowledge of memristor behavior is limited to a few physical models of which little comprehensive data collection has taken place. The purpose of this research is to collect data in search of exploitable memristor behavior by designing and implementing tests on a HP Labs Rev2 Memristor Test Board. The results are then graphed in their optimal format for conceptualizing behavioral patterns. This series of experiments has concluded the existence of an additional memristor state affecting the behavior of memristors when pulsed with positively polarized DC voltages. This effect has been observed across multiple memristors and data sets. The following pages outline the process that led to the hypothetical existence and eventual proof of this additional state of memristor behavior.

Evans, Brian R.

2013-10-01T23:59:59.000Z

455

Voltage spike detection in high field superconducting accelerator magnets  

SciTech Connect

A measurement system for the detection of small magnetic flux changes in superconducting magnets, which are due to either mechanical motion of the conductor or flux jump, has been developed at Fermilab. These flux changes are detected as small amplitude, short duration voltage spikes, which are {approx}15mV in magnitude and lasts for {approx}30 {micro}sec. The detection system combines an analog circuit for the signal conditioning of two coil segments and a fast data acquisition system for digitizing the results, performing threshold detection, and storing the resultant data. The design of the spike detection system along with the modeling results and noise analysis will be presented. Data from tests of high field Nb{sub 3}Sn magnets at currents up to {approx}20KA will also be shown.

Orris, D.F.; Carcagno, R.; Feher, S.; Makulski, A.; Pischalnikov, Y.M.; /Fermilab

2004-12-01T23:59:59.000Z

456

Monolithic high voltage nonlinear transmission line fabrication process  

DOE Patents (OSTI)

A process for fabricating sequential inductors and varistor diodes of a monolithic, high voltage, nonlinear, transmission line in GaAs is disclosed. An epitaxially grown laminate is produced by applying a low doped active n-type GaAs layer to an n-plus type GaAs substrate. A heavily doped p-type GaAs layer is applied to the active n-type layer and a heavily doped n-type GaAs layer is applied to the p-type layer. Ohmic contacts are applied to the heavily doped n-type layer where diodes are desired. Multiple layers are then either etched away or Oxygen ion implanted to isolate individual varistor diodes. An insulator is applied between the diodes and a conductive/inductive layer is thereafter applied on top of the insulator layer to complete the process. 6 figs.

Cooper, G.A.

1994-10-04T23:59:59.000Z

457

High-speed, sub-pull-in voltage MEMS switching.  

SciTech Connect

We have proposed and demonstrated MEMS switching devices that take advantage of the dynamic behavior of the MEMS devices to provide lower voltage actuation and higher switching speeds. We have explored the theory behind these switching techniques and have demonstrated these techniques in a range of devices including MEMS micromirror devices and in-plane parallel plate MEMS switches. In both devices we have demonstrated switching speeds under one microsecond which has essentially been a firm limit in MEMS switching. We also developed low-loss silicon waveguide technology and the ability to incorporate high-permittivity dielectric materials with MEMS. The successful development of these technologies have generated a number of new projects and have increased both the MEMS switching and optics capabilities of Sandia National Laboratories.

Spahn, Olga Blum; Brewer, Steven; Olsson, Roy H.; Bogart, Gregory R.; Luck, David L.; Watts, Michael R.; Shaw, Michael J.; Nielson, Gregory N.; Resnick, Paul James; Tigges, Christopher P.; Grossetete, Grant David

2008-01-01T23:59:59.000Z

458

Monolithic high voltage nonlinear transmission line fabrication process  

DOE Patents (OSTI)

A process for fabricating sequential inductors and varactor diodes of a monolithic, high voltage, nonlinear, transmission line in GaAs is disclosed. An epitaxially grown laminate is produced by applying a low doped active n-type GaAs layer to an n-plus type GaAs substrate. A heavily doped p-type GaAs layer is applied to the active n-type layer and a heavily doped n-type GaAs layer is applied to the p-type layer. Ohmic contacts are applied to the heavily doped n-type layer where diodes are desired. Multiple layers are then either etched away or Oxygen ion implanted to isolate individual varactor diodes. An insulator is applied between the diodes and a conductive/inductive layer is thereafter applied on top of the insulator layer to complete the process.

Cooper, Gregory A. (346 Primrose Dr., Pleasant Hill, CA 94523)

1994-01-01T23:59:59.000Z

459

Summary of multiterminal high-voltage direct current transmission technology  

SciTech Connect

This report summarizes the present state of multiterminal (MT) high-voltage direct current (HVDC) power transmission. The purpose is to reassess the need for HVDC circuit breakers and to identify needed research for MT HVDC. The fundamentals of this technology are presented, and previous research and development is reviewed. Although no MT HVDC systems have yet been built, many concepts have been proposed. Some require a dc breaker, and others do not. Both options have advantages and disadvantages for various applications, so the selection will depend on the proposed application. Research is needed to define operating characteristics of various MT HVDC systems. In some applications, dc breakers will be useful, so research into HVDC interruption should continue. Also, dc fault detection and control algorithms for MT systems should be studied.

Biggs, R.B.; Jewell, W.T.

1984-05-01T23:59:59.000Z

460

Sacramento Area Voltage Support Draft Environmental Impact Statement  

SciTech Connect

The Western Area Power Administration's Central Valley Project transmission system forms an integral part of the interconnected Sacramento area transmission grid. Western is contractually responsible to oversee that the system is operated in accordance with strict reliability standards. Growth in the greater Sacramento, California area and power imported from generation outside the region, have increased the demand on the interconnected electric transmission system, leading to transmission system overloads and reducing the reliability and security of the area power system. Western has prepared this Sacramento Area Voltage Support (SVS) Draft Environmental Impact Statement (EIS) in compliance with Federal laws, regulations and guidelines, principally the ''National Environmental Policy Act'' (NEPA). This Draft EIS evaluates the potential environmental effects of physical improvements to the area's power system. Enhancements are needed to improve system reliability and provide voltage support for the Sacramento area. The results of public scoping meetings, workshops, meetings with agencies, and earlier studies by Western and area utilities helped to develop a range of alternatives for analysis. The Proposed Action involves: Constructing a new double-circuit, 230-kV transmission line paralleling the existing double-circuit, 230-kV line from the O'Banion Substation to the Elverta Substation; Realigning a portion of the existing Cottonwood-Roseville single-circuit, 230-kV transmission line north of Elverta Substation; and Reconductoring the existing double-circuit, 230-kV transmission line from the Elverta Substation to the Tracy Substation. Public Hearings on the Draft EIS will be held between December 9-12, 2002. Comments on this Draft EIS are encouraged and should be sent to Ms. Loreen McMahon (above). Comments must be received by December 30, 2002.

N /A

2002-11-15T23:59:59.000Z

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While these samples are representative of the content of NLEBeta,
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461

Sacramento Area Voltage Support Final Environmental Impact Statement  

SciTech Connect

The Western Area Power Administration's Central Valley Project transmission system forms an integral part of the interconnected Sacramento area transmission grid. Western is contractually responsible to oversee that the system is operated in accordance with strict reliability standards. Growth in the greater Sacramento, California area and power imported from generation outside the region, have increased the demand on the interconnected electric transmission system, leading to transmission system overloads and reducing the reliability and security of the area power system. Western has prepared this Sacramento Area Voltage Support (SVS) Draft Environmental Impact Statement (EIS) in compliance with Federal laws, regulations and guidelines, principally the National Environmental Policy Act (NEPA). This Draft EIS evaluates the potential environmental effects of physical improvements to the area's power system. Enhancements are needed to improve system reliability and provide voltage support for the Sacramento area. The results of public scoping meetings, workshops, meetings with agencies, and earlier studies by Western and area utilities helped to develop a range of alternatives for analysis. The Proposed Action involves: (1) Constructing a new double-circuit, 230-kV transmission line paralleling the existing double-circuit, 230-kV line from the O'Banion Substation to the Elverta Substation; (2) Realigning a portion of the existing Cottonwood-Roseville single-circuit, 230-kV transmission line north of Elverta Substation; and (3) Reconductoring the existing double-circuit, 230-kV transmission line from the Elverta Substation to the Tracy Substation. Public Hearings on the Draft EIS will be held between December 9-12, 2002. Comments on this Draft EIS are encouraged and should be sent to Ms. Loreen McMahon (above). Comments must be received by December 30, 2002.

N /A

2003-09-19T23:59:59.000Z

462

BROAD ABSORPTION LINE VARIABILITY ON MULTI-YEAR TIMESCALES IN A LARGE QUASAR SAMPLE  

SciTech Connect

We present a detailed investigation of the variability of 428 C IV and 235 Si IV broad absorption line (BAL) troughs identified in multi-epoch observations of 291 quasars by the Sloan Digital Sky Survey-I/II/III. These observations primarily sample rest-frame timescales of 1-3.7 yr over which significant rearrangement of the BAL wind is expected. We derive a number of observational results on, e.g., the frequency of BAL variability, the velocity range over which BAL variability occurs, the primary observed form of BAL-trough variability, the dependence of BAL variability upon timescale, the frequency of BAL strengthening versus weakening, correlations between BAL variability and BAL-trough profiles, relations between C IV and Si IV BAL variability, coordinated multi-trough variability, and BAL variations as a function of quasar properties. We assess implications of these observational results for quasar winds. Our results support models where most BAL absorption is formed within an order-of-magnitude of the wind-launching radius, although a significant minority of BAL troughs may arise on larger scales. We estimate an average lifetime for a BAL trough along our line-of-sight of a few thousand years. BAL disappearance and emergence events appear to be extremes of general BAL variability, rather than being qualitatively distinct phenomena. We derive the parameters of a random-walk model for BAL EW variability, finding that this model can acceptably describe some key aspects of EW variability. The coordinated trough variability of BAL quasars with multiple troughs suggests that changes in 'shielding gas' may play a significant role in driving general BAL variability.

Filiz Ak, N.; Brandt, W. N.; Schneider, D. P. [Department of Astronomy and Astrophysics, Pennsylvania State University, University Park, PA 16802 (United States); Hall, P. B. [Department of Physics and Astronomy, York University, 4700 Keele St., Toronto, Ontario, M3J 1P3 (Canada); Anderson, S. F. [Astronomy Department, University of Washington, Seattle, WA 98195 (United States); Hamann, F. [Department of Astronomy, University of Florida, Gainesville, FL 32611-2055 (United States); Lundgren, B. F. [Department of Astronomy, University of Wisconsin, Madison, WI 53706 (United States); Myers, Adam D. [Department of Physics and Astronomy, University of Wyoming, Laramie, WY 82071 (United States); Pâris, I. [Departamento de Astronomía, Universidad de Chile, Casilla 36-D, Santiago (Chile); Petitjean, P. [Universite Paris 6, Institut d'Astrophysique de Paris, 75014, Paris (France); Ross, Nicholas P. [Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 92420 (United States); Shen, Yue [Harvard-Smithsonian Center for Astrophysics, 60 Garden St., MS-51, Cambridge, MA 02138 (United States); York, Don, E-mail: nfilizak@astro.psu.edu [The University of Chicago, Department of Astronomy and Astrophysics, Chicago, IL 60637 (United States)

2013-11-10T23:59:59.000Z

463

High frequency atmospheric cold plasma treatment system for materials surface processing  

Science Journals Connector (OSTI)

The paper presents a new laboratory-made plasma treatment system. The power source which generates the plasma is based on a modern half-bridge type inverter circuit working at a frequency of 4 MHz and giving an output power of about 200 W. The inverter is fed directly from the mains voltage and features high speed protection circuits for both over voltage and over current protection making the system light and easy to operate. The output of the inverter is connected to the resonant circuit formed by a Tesla coil and the dielectric barrier discharge plasma chamber. The plasma is generated at atmospheric pressure in argon helium or mixtures of helium and small quantities of argon. It is a cold discharge (Tgas plasma generates chemically active species especially O and OH which could be important in various applications such as the treatment and processing of materials surfaces.

Cristian D. Tudoran; Vasile Surducan; Sorin D. Anghel

2012-01-01T23:59:59.000Z

464

Dynamic model of the radio-frequency plasma sheath in a highly asymmetric discharge cell  

Science Journals Connector (OSTI)

A self-consistent fluid model for the radio-frequency sheath at the powered electrode of a highly asymmetric discharge cell is developed and solved. The model assumes time-independent ion motion and inertialess electrons. The voltage on the powered electrode, assumed to be sinusoidal, is shared between the powered sheath and a series resistance that represents the remainder of the discharge. The model includes ion collisions, sheath conduction currents, and secondary electron emission from the electrode surface. Model results are compared with previous sheath models and with experiment. Current wave forms predicted by the model closely resemble the nonsinusoidal current wave forms measured in highly asymmetric cells. The model accurately predicts the shape of sheath voltage wave forms, but not their dc components. The magnitudes and phases of sheath impedances predicted by the model agree with experimental measurements performed in argon discharges at pressures of 4.0–133 Pa.

M. A. Sobolewski

1997-07-01T23:59:59.000Z

465

Resonance Cone Interaction With a Self-Consistent Radio-Frequency Sheath  

Science Journals Connector (OSTI)

We study the propagation of lower-hybrid-type resonance cones in a tenuous magnetized plasma, and, in particular, their interaction with, and reflection from, the plasma sheath near a conducting wall. The sheath is modeled as a vacuum gap whose width is given by the Child-Langmuir law. The application of interest is when the resonance cones are launched (parasitically) by an ion-cyclotron radio-frequency antenna in a typical rf-heated tokamak fusion experiment. We calculate the fraction of launched voltage in the resonance cones that is transmitted to the sheath, and show that it has a sensitive thresholdlike turn on when a critical parameter reaches order unity. Above threshold, the fractional voltage transmitted to the sheath is order unity, leading to strong and potentially deleterious rf-wall interactions in tokamak rf heating experiments. Below threshold, these interactions can be avoided.

J. R. Myra and D. A. D’Ippolito

2008-11-06T23:59:59.000Z

466

Combined effects of gas pressure and exciting frequency on electron energy distribution functions in hydrogen capacitively coupled plasmas  

SciTech Connect

The combined effects of the variation of hydrogen pressure (40-400 mTorr) and exciting frequency (13.56-50 MHz) on the electron energy probability function (EEPF) and other plasma parameters in capacitively coupled hydrogen H{sub 2} discharge at fixed discharge voltage were investigated using rf-compensated Langmuir probe. At a fixed exciting frequency of 13.56 MHz, the EEPF evolved from Maxwellian-like distribution to a bi-Maxwellian distribution when the H{sub 2} pressure increased, possibly due to efficient vibrational excitation. The electron density largely increased to a peak value and then decreased with the increase of H{sub 2} pressure. Meanwhile, the electron temperature and plasma potential significantly decrease and reaching a minimum at 120 mTorr beyond, which saturated or slightly increases. On the other hand, the dissipated power and electron density markedly increased with increasing the exciting frequency at fixed H{sub 2} pressure and voltage. The electron temperatures negligibly dependent on the driving frequency. The EEPFs at low pressure 60 mTorr resemble Maxwellian-like distribution and evolve into a bi-Maxwellian type as frequency increased, due to a collisonless (stochastic) sheath-heating in the very high frequency regime, while the EEPF at hydrogen pressure {>=}120 mTorr retained a bi-Maxwellian-type distribution irrespective of the driving frequency. Such evolution of the EEPFs shape with the driving frequency and hydrogen pressure has been discussed on the basis of electron diffusion processes and low threshold-energy inelastic collision processes taking place in the discharge. The ratio of stochastic power to bulk power heating ratio is dependent on the hydrogen pressure while it is independent on the driving frequency.

Abdel-Fattah, E. [Physics Department, Faculty of Science, Zagazig University, Zagazig 44519 (Egypt); Sugai, H. [Department of Electronics and Information Engineering, Chubu University, 1200 Matsumoto-cho, Kasugai 487-8501 (Japan)

2013-02-15T23:59:59.000Z

467

February 2008 Rev 21 1/49 Very low drop voltage regulators with inhibit  

E-Print Network (OSTI)

. In the three terminal configuration the device has the same electrical performance, but is fixed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 4 Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Figure 4. Dropout voltage vs output current

Berns, Hans-Gerd

468

Electric Field Calculations on Dry-Type Medium Voltage Current Transformers.  

E-Print Network (OSTI)

??This research presents potential and electric field calculations on medium voltage (MV) epoxy insulated outdoor current transformers (CTs) using a numeri-cal calculation approach. Two designs… (more)

Lakshmichand Jain, Sandeep Kumar

2012-01-01T23:59:59.000Z

469

Object Oriented Safety Analysis of an Extra High Voltage Substation Bay  

Science Journals Connector (OSTI)

Experiences of application of the object oriented approach to safety analysis of an extra high voltage substation bay are presented. As the first step...

Bartosz Nowicki; Janusz Górski

1998-01-01T23:59:59.000Z

470

Dynamic voltage-current characteristics for a water jet plasma arc  

SciTech Connect

A virtual instrument technology is used to measure arc current, arc voltage, dynamic V-I characteristics, and nonlinear conductance for a cone-shaped water jet plasma arc under ac voltage. Experimental results show that ac arc discharge mainly happens in water vapor evaporated from water when heated. However, due to water's cooling effect and its conductance, arc conductance, reignition voltage, extinguish voltage, and current zero time are very different from those for ac arc discharge in gas work fluid. These can be valuable to further studies on mechanism and characteristics of plasma ac discharge in water, and even in gas work fluid.

Yang Jiaxiang; Lan Sheng; Xu Zuoming [College of Electrical and Electronic Engineering, Harbin University of Science and Technology, Harbin, Heilongjiang 150040 (China)

2008-05-05T23:59:59.000Z

471

Lab Trials of an Electricity Transmission Line Voltage Sensor Based on Thermally Poled Silica Fibre  

Science Journals Connector (OSTI)

Voltage sensing using helically coiled lengths of thermally poled twin-hole silica optical fibre is presented. Lab accuracy test results showing good linearity and signal to noise...

Michie, Andrew M; Hambley, Philip; Bassett, Ian M; Haywood, John H; Henry, Peter; Ingram, John

472

The design of an A-C voltage regulator using a Wein Bridge detector  

E-Print Network (OSTI)

equipment, which in turn demands a mox'e closely regulated power supply. In satisfying these demands there have been many kinds of voltage regulators designed, constructed, and needs A voltage regulator oonsists essentially of two pax'ts, the "detectox...-V, 424-8, 470 3, 499-503 1950 4. Patchett, G. N. , "The Theory of Nonlinear Bridge Circuit Applied to Voltage Stabilizers, " J. I . E. E . , Vol. 93, Pt. III, p. 18 (1948). 5. Choudbury, J. K. t Das Gupta, S. C. , and Sen, P. C, , "An A-C Voltage...

Brown, Richard True

2012-06-07T23:59:59.000Z

473

Solid State NMR Studies and Local Structure of Voltage Fade Materials  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

with the Voltage Fade Team Michael Slater, Jason Croy, Kevin Gallagher, Christopher Johnson, Yang Ren DOE Vehicle Technologies Program Annual Merit Review Arlington, VA May 13 -...

474

Consideration of 34. 5 KV as an in-plant voltage for a large industrial user  

SciTech Connect

Traditionally, the in-plant distribution voltage for a large refinery or petrochemical complex has been 13.8 kV. Selection of this voltage level was dictated primarily by economic factors, simply because in most cases the magnitude of the loads or the lengths of the feeders did not produce sufficient savings to compensate for the costlier higher voltage switchgear. This paper presents some engineering and cost considerations for distribution at 34.5 kV and attempts to show that this voltage level is both economically and technically feasible for large electrical systems.

Niculescu, T.D.; Regan, R.R.

1983-09-01T23:59:59.000Z

475

E-Print Network 3.0 - affects voltage-gated calcium Sample Search...  

NLE Websites -- All DOE Office Websites (Extended Search)

modulate neuronal voltage-gated calcium cur- rents, we performed a whole-cell patch... that hippocampal neurons in an astrocyte-enriched environment show augmentation of...

476

Abstract--Heart rate variability (HRV) is frequently used to measure autonomic nervous system (ANS) activity. However,  

E-Print Network (OSTI)

1 of 4 Abstract--Heart rate variability (HRV) is frequently used to measure autonomic nervous frequency (HF) ratio with little change in mean heart rate. Results suggest that nicotine affects both components may yield erroneous results. Keywords--Autonomic regulation, heart rate variability, Lomb

477

H{sup -} beam extraction from a cesium seeded field effect transistor based radio frequency negative hydrogen ion source  

SciTech Connect

H{sup -} beam was successfully extracted from a cesium seeded ion source operated using a field effect transistor inverter power supply as a radio frequency (RF) wave source. High density hydrogen plasma more than 10{sup 19} m{sup -3} was obtained using an external type antenna with RF frequency of lower than 0.5 MHz. The source was isolated by an isolation transformer and H{sup -} ion beam was extracted from a single aperture. Acceleration current and extraction current increased with the increase of extraction voltage. Addition of a small amount of cesium vapor into the source enhanced the currents.

Ando, A.; Matsuno, T.; Funaoi, T.; Tanaka, N. [School of Engineering, Tohoku University, Sendai 980-8579 (Japan); Tsumori, K.; Takeiri, Y. [National Institute for Fusion Science, Toki 509-5292 (Japan)

2012-02-15T23:59:59.000Z

478

On the Source of Midlatitude Low-Frequency Variability. Part II: Nonlinear Equilibration of Weather Regimes  

Science Journals Connector (OSTI)

We present a new statistical-dynamical approach to the concept of weather regimes, including the effect of tralisients, without any assumption other than scale separation. The method is applied to a quasi-geostrophic channel model without ...

Robert Vautard; Bernard Legras

1988-10-01T23:59:59.000Z

479

A spectrally accurate direct solution technique for frequency-domain scattering problems with variable media  

Science Journals Connector (OSTI)

This paper presents a direct solution technique for the scattering of time-harmonic waves from a bounded region of the plane in which the wavenumber varies smoothly in space. The method constructs the interior...

Adrianna Gillman; Alex H. Barnett; Per-Gunnar Martinsson

2014-06-01T23:59:59.000Z

480

Heavy Daily Precipitation Frequency over the Contiguous United States: Sources of Climatic Variability and Seasonal Predictability  

Science Journals Connector (OSTI)

By matching large-scale patterns in climate fields with patterns in observed station precipitation, this work explores seasonal predictability of precipitation in the contiguous United States for all seasons. Although it is shown that total ...

Alexander Gershunov; Daniel R. Cayan

2003-08-01T23:59:59.000Z

Note: This page contains sample records for the topic "frequency variable voltage" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


481

A Method for Evaluating the Application of Variable Frequency Drives with Coal Mine Ventilation Fans.  

E-Print Network (OSTI)

??The adjustable-pitch setting on an axial-flow fan is the most common method of controlling airflow for primary coal mine ventilation. With this method, the fan… (more)

Murphy, Tyson M.

2006-01-01T23:59:59.000Z

482

Low-frequency variability of currents in the deepwater eastern Gulf of Mexico  

E-Print Network (OSTI)

and shorter time scales. A model utility test for the least squares fit of modeled to observed velocity shows that the second baroclinic mode is useful to the statistical model during 50 – 85 % of the mooring deployment, and is particularly necessary...

Cole, Kelly Lynne

2009-05-15T23:59:59.000Z

483

Vortex precession frequency and its amplitude-dependent shift in cylindrical nanomagnets  

SciTech Connect

Frequency of free magnetic vortex precession in circular soft ferromagnetic nano-cylinders (magnetic dots) of various sizes is an important parameter, used in design of spintronic devices (such as spin-torque microwave nano-oscillators) and characterization of magnetic nanostructures. Here, using a recently developed collective-variable approach to non-linear dynamics of magnetic textures in planar nano-magnets, this frequency and its amplitude-dependent shift are computed analytically and plotted for the full range of cylinder geometries. The frequency shift is positive in large planar dots, but becomes negative in smaller and more elongated ones. At certain dot dimensions, a zero frequency shift is realized, which can be important for enhancing frequency stability of magnetic nano-oscillators.

Metlov, Konstantin L., E-mail: metlov@fti.dn.ua [Donetsk Institute for Physics and Technology NAS, Donetsk 83114 (Ukraine)

2013-12-14T23:59:59.000Z

484

Experimental characterization of faults on low-voltage systems  

E-Print Network (OSTI)

INTRODUCTION . Page II EXISTING DETECTION SCHEMES AND RESEARCH OBJECTIVES 8 Existing Detection Schemes Research Objectives III THEORY OF ARCS AND ARCING FAULTS 8 15 17 Formation of Spark Arc Chracteristics 17 18 IV FIELD TEST INSTRUMENTATION... EQUIPMENT . , V DESCRIPTION OF TESTS VI FIELD TESTS - GENERAL . . 30 VII DATA ANALYSIS, OBSERVATION AND SUMMARY . . 43 Time Domain Analysis . Frequency Domain Analysis Comparison with 15 kV Systems . Summary of Results . 44 56 67 72 REFERENCES...

Ahmed, Jubayer

1992-01-01T23:59:59.000Z

485

High frequency fast wave current drive for DEMO  

SciTech Connect

A steady-state tokamak reactor (SSTR) requires a high efficiency current drive system, from plug to driven mega-amps. RF systems working in the ion-cyclotron range of frequencies (ICRF) have high efficiency from plug to antenna but a limited current drive (CD) efficiency and centrally peaked CD profiles. The latter feature is not adequate for a SSTR where the current should be sufficiently broad to keep the central safety factor (possibly significantly) above 1. In addition, the fact that the fast wave (FW) is evanescent at the edge limits coupling, requiring high voltage operation, which makes the system dependent on plasma edge properties and prone to arcing, reducing its reliability. A possible way to overcome these weaknesses is to operate at higher frequency (10 times or more the cyclotron frequency). The advantages are: (1) The coupling can be much better (waves propagate in vacuum) if the parallel refractive index n{sub ||} is kept below one, (2) The FW group velocity tends to align to the magnetic field, so the power circumnavigates the magnetic axis and can drive off-axis current, (3) Due to the latter property, n{sub ||} can be upshifted along the wave propagation path, allowing low n{sub ||} launch (hence good coupling, large CD efficiency) with ultimately good electron absorption (which requires higher n{sub ||}. Note however that the n{sub ||} upshift is a self-organized feature, that electron absorption is in competition with {alpha}-particle absorption and that uncoupling of the FW from the lower hybrid resonance at the edge requires n{sub ||} slightly above one. The latter possibly counterproductive features might complicate the picture. The different aspects of this potentially attractive off-axis FWCD scheme are discussed.

Koch, R.; Lerche, E.; Van Eester, D. [LPP/ERM-KMS, Association 'EURATOM-Belgian State', 1000 Brussels, TEC Partner (Belgium); Nightingale, M. [Culham Centre for Fusion Energy, Abingdon OX14 3DB (United Kingdom)

2011-12-23T23:59:59.000Z

486

An Ensemble Empirical Mode Decomposition Approach for Voltage Sag Detection in a Smart Grid Context  

E-Print Network (OSTI)

An Ensemble Empirical Mode Decomposition Approach for Voltage Sag Detection in a Smart Grid Context Yassine Amirat1,2 , Mohamed Benbouzid2 , Tianzhen Wang3 and Sylvie Turri2 Abstract­Smart grids have become, using the instantaneous power for voltage sags detection in smart grids. Copyright © 2013 Praise Worthy

Brest, Université de

487

Hydroelectric Voltage Generation Based on Water-Filled Single-Walled Carbon Nanotubes  

Science Journals Connector (OSTI)

Hydroelectric Voltage Generation Based on Water-Filled Single-Walled Carbon Nanotubes ... The hydroelectric voltage generator can be expressed by the model illustrated in Figure 6a and b. ... Individual water-filled single-walled carbon nanotubes as hydroelectric power converters ...

Quanzi Yuan; Ya-Pu Zhao

2009-04-21T23:59:59.000Z

488

Optimal Placement of the Wind Generators in the Medium Voltage Power Grid  

Science Journals Connector (OSTI)

The minimization of power losses in the medium voltage (MV) grid requires adjustment of network of power sources. This problem is particularly important for renewable energy sources, for example for the farms of wind generators. Their placement and nominal ... Keywords: medium voltage power grid, wind generators, genetic algorithms, parallel processing

Andrzej Jordan; Ryszard Szczebiot; Carsten Maple; Slawomir Cieslik

2011-04-01T23:59:59.000Z

489

Integrating a Feature Selection Algorithm for Classification of Voltage Sags Originated in Transmission and Distribution Networks  

Science Journals Connector (OSTI)

As a global problem in the power quality area, voltage sags are matter of high interest for both utilities and customers. With a view to resolving the problem of sag source location in the power network, this paper introduces a new method based on dimension ... Keywords: Direction, Hybrid Method, Mpca, Voltage Sag

Abbas Khosravi; Toni Martinez; Joaquim Melendez; Joan Colomer; Jorge Sanchez

2007-06-01T23:59:59.000Z

490

A genetic algorithm approach to voltage-VAR control in systems with distributed generation  

Science Journals Connector (OSTI)

This paper presents a case study that highlights the influences which the connection of distributed generation sources may have over the solutions of reactive power compensation and voltage control already existing in a given network. The problem of ... Keywords: distributed generation, genetic algorithms, renewable sources, voltage-var control

Iulia Coroama; Mihai Gavrilas; Ovidiu Ivanov

2010-10-01T23:59:59.000Z

491

A Static Pattern-Independent Technique for Power Grid Voltage Integrity Verification  

E-Print Network (OSTI)

A Static Pattern-Independent Technique for Power Grid Voltage Integrity Verification Dionysios Design verification must include the power grid. Checking that the voltage on the power grid does) the obviously large size of the power grids for modern high-performance chips, and ii) the difficulty of setting

Najm, Farid N.

492

A Static PatternIndependent Technique for Power Grid Voltage Integrity Verification #  

E-Print Network (OSTI)

A Static Pattern­Independent Technique for Power Grid Voltage Integrity Verification # Dionysios Design verification must include the power grid. Checking that the voltage on the power grid does) the obviously large size of the power grids for modern high­performance chips, and ii) the di#culty of setting

Najm, Farid N.

493

LM193/LM293/LM393/LM2903 Low Power Low Offset Voltage Dual Comparators  

E-Print Network (OSTI)

LM193/LM293/LM393/LM2903 Low Power Low Offset Voltage Dual Comparators General Description The LM clock timers; multivibrators and high voltage digital logic gates. The LM193 series was designed to directly interface with TTL and CMOS. When operated from both plus and minus power supplies, the LM193

Lanterman, Aaron

494

Chapter 19. High Voltage Insulation, Diagnostics and Energetic Electron and Photon Beam Interactions  

E-Print Network (OSTI)

Chapter 19. High Voltage Insulation, Diagnostics and Energetic Electron and Photon Beam Interactions 19-1 High Voltage Insulation, Diagnostics and Energetic Electron and Photon Beam Interactions 1. DC Properties of Modern Filled Epoxy Insulation Academic and Research Staff Dr. Chathan Cooke Sponsor

495

Creation of Onset Voltage Hash by Anode Spots in a Magnetoplasmadynamic Thruster  

E-Print Network (OSTI)

Creation of Onset Voltage Hash by Anode Spots in a Magnetoplasmadynamic Thruster Luke Uribarri flow rate) of onset voltage fluctuations in a magnetoplasmadynamic thruster operating with three anode materials, and an anode spot model is presented which provides a physical explanation for the properties

Choueiri, Edgar

496

The Onset of Voltage Hash and its Relationship to Anode Spots in Magnetoplasmadynamic Thrusters  

E-Print Network (OSTI)

The Onset of Voltage Hash and its Relationship to Anode Spots in Magnetoplasmadynamic Thrusters, 08544 A phenomenological model is developed to elucidate the relationship between voltage hash and anode electromagnetic force density leads to a mass depletion in the anode region which, in turn, leads to a disparity

Choueiri, Edgar

497

Importance of the Equlibrium Node in Preventing the Voltage Collapse Occurs in the Wind Power System  

E-Print Network (OSTI)

Importance of the Equlibrium Node in Preventing the Voltage Collapse Occurs in the Wind Power collapse will occurs in a wind power system is discussed next. The method of power flow calculation is the specific analysis of a given simplified wind power system. Keywords--voltage collapse; Newton

Lavaei, Javad

498

Meter Any Wire, Anywhere by Virtualizing the Voltage Channel Thomas Schmid, David Culler, Prabal Dutta  

E-Print Network (OSTI)

Meter Any Wire, Anywhere by Virtualizing the Voltage Channel Thomas Schmid, David Culler, Prabal}@eecs.umich.edu culler@cs.berkeley.edu Abstract AC power meters require both voltage and current to be sampled physical proximity and fed into a single power metering de- vice. In this paper, we explore the viability

Dutta, Prabal

499

Onset Voltage Hash and Anode Spots in Quasi-Steady Magnetoplasmadynamic  

E-Print Network (OSTI)

Onset Voltage Hash and Anode Spots in Quasi-Steady Magnetoplasmadynamic Thrusters Luke Uribarri: Edgar Y. Choueiri November 2008 #12;ONSET VOLTAGE HASH AND ANODE SPOTS IN QUASI noise ("hash") and anode damage in a self-field, quasi-steady magnetoplasmadynamic thruster (MPDT

Choueiri, Edgar

500

Scaling of Anode Sheath Voltage Fall with the Operational Parameters in Applied-Field MPD  

E-Print Network (OSTI)

Scaling of Anode Sheath Voltage Fall with the Operational Parameters in Applied-Field MPD Thrusters (EPPDyL) Princeton University, Princeton, NJ, 08544, USA Scaling laws for the anode sheath voltage fall in applied-field MPD thrusters are derived in order to better understand the physics behind anode sheath

Choueiri, Edgar