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Note: This page contains sample records for the topic "frequency variable voltage" from the National Library of EnergyBeta (NLEBeta).
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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 speed constant frequency constant voltage alternator. Annual report  

DOE Green Energy (OSTI)

A test alternator is operated with digital control of its output frequency for variable shaft speed. The machine is a two-pole alternator with power removed through slip rings. The output frequency of the alternator is controlled by rotating the field by stepping through sixteen coils around the rotor. Usually four coils are active at one time. The rotating field in the stationary coils of the stator is controlled by microcircuits. The control circuits are constructed with available low-cost, low-power integrated circuits (ICs). The test results from the first test alternator indicate the feasibility of using this type of alternator to convert available wind power directly to usable 60 hertz power.

Grannemann, W.W.; Yang, C.E.; Seo, P.H.

1980-07-01T23:59:59.000Z

2

High frequency breakdown voltage  

SciTech Connect

This report contains information about the effect of frequency on the breakdown voltage of an air gap at standard pressure and temperature, 76 mm Hg and O{degrees}C, respectively. The frequencies of interest are 47 MHz and 60 MHz. Additionally, the breakdown in vacuum is briefly considered. The breakdown mechanism is explained on the basis of collision and ionization. The presence of the positive ions produced by ionization enhances the field in the gap, and thus determines the breakdown. When a low-frequency voltage is applied across the gap, the breakdown mechanism is the same as that caused by the DC or static voltage. However, when the frequency exceeds the first critical value f{sub c}, the positive ions are trapped in the gap, increasing the field considerably. This makes the breakdown occur earlier; in other words, the breakdown voltage is lowered. As the frequency increases two decades or more, the second critical frequency, f{sub ce}, is reached. This time the electrons start being trapped in the gap. Those electrons that travel multiple times across the gap before reaching the positive electrode result in an enormous number of electrons and positive ions being present in the gap. The result is a further decrease of the breakdown voltage. However, increasing the frequency does not decrease the breakdown voltage correspondingly. In fact, the associated breakdown field intensity is almost constant (about 29 kV/cm).The reason is that the recombination rate increases and counterbalances the production rate, thus reducing the effect of the positive ions` concentration in the gap. The theory of collision and ionization does not apply to the breakdown in vacuum. It seems that the breakdown in vacuum is primarily determined by the irregularities on the surfaces of the electrodes. Therefore, the effect of frequency on the breakdown, if any, is of secondary importance.

Chu, Thanh Duy

1992-03-01T23:59:59.000Z

3

High voltage variable diameter insulator  

DOE Patents (OSTI)

A high voltage feedthrough assembly (10) having a tubular insulator (15) extending between the ground plane ring (16) and the high voltage ring (30). The insulator (15) is made of Pyrex and decreases in diameter from the ground plane ring (16) to the high voltage ring (30), producing equipotential lines almost perpendicular to the wall (27) of the insulator (15) to optimize the voltage-holding capability of the feedthrough assembly (10).

Vanecek, David L. (Martinez, CA); Pike, Chester D. (Pinole, CA)

1984-01-01T23:59:59.000Z

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

Multi-winding Homopolar Electric Machine Offers Variable Voltage ...  

Wind Energy Industrial Technologies Multi-winding Homopolar Electric Machine Offers Variable Voltage at Low Rotational Speed Oak Ridge National Laboratory. Contact ...

6

Quartz crystal microbalance based on passive frequency to voltage converter  

SciTech Connect

In dynamics of evaporation or drying of microdrops from a solid surface, a faster and precise quartz crystal microbalance (QCM) is needed. The fast QCM based on frequency to voltage converter is an attractive and powerful tool in the investigation of the dynamic regime of evaporation to translate the frequency shift in terms of a continuous voltage change. The frequency shift monitoring in fast QCM applications is a real challenge for electronic processing interface. Originally developed as a frequency shift processing interface, this novel passive frequency to voltage converter can produce faster, stable, and accurate results in regard to the QCM sensor behavior. In this article, the concept and circuit of passive frequency to voltage converter will be explained followed by static and dynamic characterization. Experimental results of microdrops evaporation will be given.

Burda, Ioan; Tunyagi, Arthur [Department of Physics, Babes-Bolyai University, Cluj-Napoca, 400084 (Romania)

2012-02-15T23:59:59.000Z

7

ESP-The Electrical submersible pump. Part 7. Applying variable frequency drives to ESPs  

SciTech Connect

To keep pace with technology, the oil industry has begun using variable frequency drives on electrical submersible pumps. Applying variable frequency drives on ESPs began seriously in 1977. In March 1983, there were approximately 350 variable frequency drives successfully operating on electrical submersible pumps throughout the world. Three types of variable frequency drives available today are the current source inverter, the pulse width modulation, and the variable voltage source inverter. As all three types have good points and bad, a short discussion of each type is essential to understand why the variable voltage inverter is used most often in oil field applications and why it has been a success. A current source inverter typically uses a phasecontrolled rectifier to generate variable DC current. The phase-controlled rectifier produces the required current which is subsequently filtered by a DC link reactor. The inverter then produces the desired variable frequency current and the motor voltage varies with load.

Watson, A.J.

1983-11-15T23:59:59.000Z

8

Rank based dynamic voltage and frequency scaling fortiled graphics processors  

Science Conference Proceedings (OSTI)

With increasing interest in sophisticated graphics capabilities in mobile systems, energy consumption of graphics hardware is becoming a major design concern in addition to the traditional performance enhancement criteria. Our study of various modern ... Keywords: dynamic voltage and frequency scaling, graphics processor, low power, workload prediction

B.V.N Silpa; Gummidipudi Krishnaiah; Preeti Ranjan Panda

2010-10-01T23:59:59.000Z

9

Offshore operations report. ESP - the electrical submersible pump. Part 7. Applying variable frequency drives to esps  

SciTech Connect

The oil industry has begun using variable frequency drives on electric submersible pumps. In March 1983, there were approximately 350 variable frequency drives successfully operating on electrical submersible pumps throughout the world. Three types of variable frequency drives available are the current source inverter, the pulse width modulation, and the variable voltage source inverter. A short discussion of each type is given to explain why the variable voltage inverter is used most often in oil field applications and why it has been a success.

Watson, A.J.

1983-11-15T23:59:59.000Z

10

A variable voltage MPPT control method for photovoltaic generation system  

Science Conference Proceedings (OSTI)

To increase the output efficiency of a photovoltaic (PV) generation system it is important to have an efficient maximum power point tracking (MPPT) technique. This paper describes the analysis, design and implementation of an efficient tracking method ... Keywords: maximum power point tracking (MPPT), photovoltaic generation system, pulse-width-modulation (PWM), solar energy, variable voltage

Liu Liqun; Wang Zhixin

2009-04-01T23:59:59.000Z

11

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

E-Print Network (OSTI)

Variable frequency drives (VFD) and subsea (umbilical) cables are frequently used in electrical submersible pump (ESP) systems for offshore platforms. There are two basic system configurations for ESP systems; VFD can be installed on the platform and the motor is connected to it through an umbilical cable, and VFD and the motor are installed closely and they are connected to the system through an umbilical cable. In this thesis, the pros and cons of each configuration are mentioned, but the focus is on the system with a VFD controlled motor through a long umbilical cable. A 36-pulse VFD is studied. Since multilevel VFDs have high frequency harmonics, high frequency modeling of the umbilical cable is used, and skin effect is also taken into consideration in the cable. The effect of the interactions between the umbilical cable and high frequency harmonics on the motor terminal voltage is explored.

Ozkentli, Esra

2012-08-01T23:59:59.000Z

12

Energy conversion apparatus for supplying variable voltage direct current power to an electrically propelled vehicle  

SciTech Connect

A synchronous machine, operable as both a motor and a generator, is mounted on an electrically powered vehicle, such as a mine shuttle car, and includes a plurality of conductors having connections that are detachably engagable with receptacles of a stationary power bank. Engagement of the conductors with the receptacles supplies variable voltage alternating current power to the machine. The machine is drivingly connected to a flywheel on the vehicle and, operating as a motor, energizes the flywheel to store a preselected amount of mechanical energy. The electrical connection between the vehicle and the power bank is opened after the flywheel has been sufficiently charged. The stored energy in the flywheel is then available to drive the machine as a generator and produce high frequency, three phase, alternating current power. The generated power is transmitted to a full wave silicon controlled rectifier that converts the alternating current power to direct current for powering the traction motors of the vehicle. A variable voltage controller is connected to the rectifier and actuates the rectifier to supply direct current at a selected voltage level. The controller is responsive to an operator foot pedal. By manually depressing the foot pedal to a selected position, the voltage level of the rectified current is controlled. Thus, the speed of the traction motors is adjustable topropel the vehicle at a speed within a given range. After a portion of the energy stored by the flywheel is consumed, the vehicle is returned to the power bank to replenish the energy supply.

Jamison, W.B.; Burr, J.F.

1976-09-07T23:59:59.000Z

13

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

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 summarize… (more)

Rountree, Barry

2009-01-01T23:59:59.000Z

15

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

E-Print Network (OSTI)

The subject of radio-frequency interference (RFI) generated by high-voltage transmission lines has long been of both academic and commercial interest because of concerns about

Patrick C. Crane

2010-01-01T23:59:59.000Z

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

A Low Power, Low Voltage, Fully Differential CMOS Variable Gain Amplifier.  

E-Print Network (OSTI)

?? This research presents a low voltage (0.8 V) fully differential CMOS variable gain amplifier. SPECTRE simulations on the designed amplifier show a -17 dB… (more)

Siddiqui, Muhammad Yousuf

2011-01-01T23:59:59.000Z

18

Cooperative frequency control with a multi-terminal high-voltage DC network  

Science Conference Proceedings (OSTI)

We consider frequency control in power systems made of several non-synchronous AC areas connected by a multi-terminal high-voltage direct current (HVDC) grid. We propose two HVDC control schemes to make the areas collectively react to power imbalances, ... Keywords: Decentralized control, Frequency control, HVDC systems, Power system control

Alain Sarlette; Jing Dai; Yannick Phulpin; Damien Ernst

2012-12-01T23:59:59.000Z

19

Information Theory and Predictability for Low-Frequency Variability  

Science Conference Proceedings (OSTI)

A predictability framework, based on relative entropy, is applied here to low-frequency variability in a standard T21 barotropic model on the sphere with realistic orography. Two types of realistic climatology, corresponding to different heights ...

Rafail Abramov; Andrew Majda; Richard Kleeman

2005-01-01T23:59:59.000Z

20

Homoclinic Dynamics: A Scenario for Atmospheric Ultralow-Frequency Variability  

Science Conference Proceedings (OSTI)

In this paper, a link will be established between atmospheric ultralow-frequency variability (ULFV) and the occurrence of homoclinic dynamics in models of large-scale atmospheric flow. It is known that uncoupled atmosphere models possess ...

Daan T. Crommelin

2002-05-01T23:59:59.000Z

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

Low-Frequency Variability in the Wind-Driven Circulation  

Science Conference Proceedings (OSTI)

The origins of low-frequency variability in a simple homogenous ocean model, forced by a double gyre Ekman suction, are examined numerically. It is found that irregular, large amplitude vacillations in the structure of the circulation typify the ...

S. P. Meacham

2000-02-01T23:59:59.000Z

22

Energy aware dynamic voltage and frequency selection for real-time systems with energy harvesting  

Science Conference Proceedings (OSTI)

In this paper, an energy aware dynamic voltage and frequency selection (EA-DVFS) algorithm is proposed. The EA-DVFS algorithm adjusts the processor's behavior depending on the summation of the stored energy and the harvested energy in a future duration. ...

Shaobo Liu; Qinru Qiu; Qing Wu

2008-03-01T23:59:59.000Z

23

PEV-Based Combined Frequency and Voltage Regulation for Smart Grid  

E-Print Network (OSTI)

PEV-Based Combined Frequency and Voltage Regulation for Smart Grid Chenye Wu, Student Member, IEEE benefit both users and utilities. Index Terms--Smart grid, plug-in electric vehicles, demand side the power grid by providing various ancillary services. In fact, recent studies have suggested that PEVs can

Wu, Chenye

24

A new measurement technique for tracking voltage phasors, local system frequency, and rate of change of frequency  

Science Conference Proceedings (OSTI)

With the advent of Substation Computer Systems dedicated to protection, control and data logging functions in a Substation, it becomes possible to develop new applications which can utilize the processing power available within the substation. The microcomputer based Symmetrical Component Distance Relay (SCDR) described in the references cited at the end of this paper possesses certain characteristics which facilitate real-time monitoring of positive sequence voltage phasor at the local power system bus. With a regression analysis the frequency and rate-of-change of frequency at the bus can also be determined from the positive sequence voltage phase angle. This paper describes the theoretical basis of these computations and describes results of experiments performed in the AEP power system simulation laboratory. Plans for future field tests on the AEP system are also outlined.

Phadke, A.G.; Adamiak, M.G.; Thorp, J.S.

1983-05-01T23:59:59.000Z

25

On the application of radio frequency voltages to ion traps via helical resonators  

E-Print Network (OSTI)

Ions confined using a Paul trap require a stable, high voltage and low noise radio frequency (RF) potential. We present a guide for the design and construction of a helical coil resonator for a desired frequency that maximises the quality factor for a set of experimental constraints. We provide an in-depth analysis of the system formed from a shielded helical coil and an ion trap by treating the system as a lumped element model. This allows us to predict the resonant frequency and quality factor in terms of the physical parameters of the resonator and the properties of the ion trap. We also compare theoretical predictions with experimental data for different resonators, and predict the voltage applied to the ion trap as a function of the Q-factor, input power and the properties of the resonant circuit.

Siverns, J D; Weidt, S; Hensinger, W K

2011-01-01T23:59:59.000Z

26

On the application of radio frequency voltages to ion traps via helical resonators  

E-Print Network (OSTI)

Ions confined using a Paul trap require a stable, high voltage and low noise radio frequency (RF) potential. We present a guide for the design and construction of a helical coil resonator for a desired frequency that maximises the quality factor for a set of experimental constraints. We provide an in-depth analysis of the system formed from a shielded helical coil and an ion trap by treating the system as a lumped element model. This allows us to predict the resonant frequency and quality factor in terms of the physical parameters of the resonator and the properties of the ion trap. We also compare theoretical predictions with experimental data for different resonators, and predict the voltage applied to the ion trap as a function of the Q-factor, input power and the properties of the resonant circuit.

J. D. Siverns; L. R. Simkins; S. Weidt; W. K. Hensinger

2011-06-24T23:59:59.000Z

27

Eddy-Induced Instability for Low-Frequency Variability  

Science Conference Proceedings (OSTI)

Synoptic eddy–mean flow interaction has been recognized as one of the key sources for extratropical low-frequency variability. In this paper, the underlying dynamics of this interaction are examined from the perspective of a synoptic eddy-induced ...

F-F. Jin

2010-06-01T23:59:59.000Z

28

Section 5.7.2 Variable-Frequency Motors: Greening Federal Facilities...  

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

major VFD designs are commonly used: pulse- width modulation (PWM), current source inverter (CSI), and variable voltage inverter (VVI). A fourth type, the flux vector PWM drive,...

29

Combined transmission distribution load flow model employing system reduction and voltage variable load representation  

SciTech Connect

In the few decades since its introduction the digital computer has found widespread application within the electric power industry. One of the more fruitful areas for its utilization has been in the determination of the steady-state voltage conditions throughout the system. A power system naturally breaks down into two very distinct parts: transmission and distribution, and traditionally, the voltage problem has been separated the same way. In the transmission system it is referred to as a load flow problem, and in the distribution part it is called a voltage profile. In addition, the loads are often treated differently. Transmission loads are usually considered to be constant power, and the equations that result are therefore nonlinear. In the distribution portion the loads, though specified in terms of power, are sometimes handled as constant impedances, with linear equations. This work produced a new model wherein a mesh transmission system is combined with a radial distribution system and they are solved simultaneously. A system reduction technique is used to eliminate part of the transmission system from consideration, and thereby keep the problem at a manageable size. The solution algorithm incorporates a voltage variable load model which approximates the behavior of real loads more nearly than the common representations.

Enouen, P.W.

1985-01-01T23:59:59.000Z

30

Variable Frequency Operations of an Offshore Wind Power Plant with HVDC-VSC: Preprint  

DOE Green Energy (OSTI)

In this paper, a constant Volt/Hz operation applied to the Type 1 wind turbine generator. Various control aspects of Type 1 generators at the plant level and at the turbine level will be investigated. Based on DOE study, wind power generation may reach 330 GW by 2030 at the level of penetration of 20% of the total energy production. From this amount of wind power, 54 GW of wind power will be generated at offshore wind power plants. The deployment of offshore wind power plants requires power transmission from the plant to the load center inland. Since this power transmission requires submarine cable, there is a need to use High-Voltage Direct Current (HVDC) transmission. Otherwise, if the power is transmitted via alternating current, the reactive power generated by the cable capacitance may cause an excessive over voltage in the middle of the transmission distance which requires unnecessary oversized cable voltage breakdown capability. The use of HVDC is usually required for transmission distance longer than 50 kilometers of submarine cables to be economical. The use of HVDC brings another advantage; it is capable of operating at variable frequency. The inland substation will be operated to 60 Hz synched with the grid, the offshore substation can be operated at variable frequency, thus allowing the wind power plant to be operated at constant Volt/Hz. In this paper, a constant Volt/Hz operation applied to the Type 1 wind turbine generator. Various control aspects of Type 1 generators at the plant level and at the turbine level will be investigated.

Gevorgian, V.; Singh, M.; Muljadi, E.

2011-12-01T23:59:59.000Z

31

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 in properly applying VFDs. The benefits and pitfalls in applying VFDs that will be addressed by this paper include- Benefits: Energy Savings, Improved Process Control, “Soft Start” Reduced Mechanical Stress, Improved Electrical System Power Factor, and Pitfalls: Motor Acoustic Noise, Motor Heating. This paper is intended for plant engineers and maintenance personnel who have some practical experience with electrical and mechanical equipment, but are not VFD experts.

Petro, D.

1993-03-01T23:59:59.000Z

32

Jet Jumping: Low-Frequency Variability in the Southern Ocean  

Science Conference Proceedings (OSTI)

The authors study intrinsic variability in the position of jets in a ?-plane channel ocean with simple topography using a quasigeostrophic numerical model. This study links the variability in jet position with abyssal anticyclones that form as a ...

Christopher C. Chapman; Andrew McC. Hogg

2013-05-01T23:59:59.000Z

33

CMOS Open Defect Detection Based on Supply Current in Time-Variable Electric Field and Supply Voltage Application  

Science Conference Proceedings (OSTI)

In this paper, a new test method is proposed for detecting open defects in CMOS ICs. The method is based on supply current of ICs generated by applying time-variable supply voltage and electric field from the outside of the ICs. The feasibility of the ...

Masaki Hashizume; Masahiro Ichimiya; Hiroyuki Yotsuyanagi; Takeomi Tamesada

2001-11-01T23:59:59.000Z

34

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

35

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.

Duckworth, Douglas C. (Knoxville, TN); Marcus, R. Kenneth (Clemson, SC); Donohue, David L. (Vienna, AT); Lewis, Trousdale A. (Oak Ridge, TN)

1994-01-01T23:59:59.000Z

36

Simulation of North Atlantic Low-Frequency SST Variability  

Science Conference Proceedings (OSTI)

The role of atmospheric circulation anomalies in generating midlatitude sea surface temperature (SST) variability is investigated by means of ocean general circulation model (OGCM) experiments, in which observed winds are prescribed during the ...

Ute Luksch

1996-09-01T23:59:59.000Z

37

Mechanisms of Monsoon Low-Frequency Variability: Surface Hydrological Effects  

Science Conference Proceedings (OSTI)

Observations indicate that monsoon systems are characterized by orderly large-scale and low-frequency variations. With a time scale of two weeks and sometimes longer, regions of ascending motion are observed to form to the north of the equator ...

Peter J. Webster

1983-09-01T23:59:59.000Z

38

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 stresses on shafts and couplings, and reduce the lifetime of these mechanical parts. Long before the designed lifetime, the mechanical train may encounter failure. This thesis focuses on VFDs with voltage source rectifiers for squirrel-cage induction motors of open-loop Volts/Hertz and closed-loop Field Oriented Control (FOC). First, the torsional vibration problems induced by VFDs are introduced. Then, the mathematical model for a squirrel-cage induction motor is given. Two common control methods used in VFD are discussed - open-loop Volts/Hertz and closed-loop FOC. SimPowerSystems and SimMechanics are used as the modeling software for electrical systems and mechanical systems respectively. Based on the models and software, two interface methods are provided for modeling the coupled system. A simple system is tested to verify the interface methods. The study of open-loop Volts/Hertz control method is performed. The closed-form of electromagnetic torque sideband frequency due to Pulse Width Modulation is given. A torsional resonance case is illustrated. The effects of non-ideal power switches are studied, which shows little in uence on the system response but which uses little energy consumption. A study of a non-ideal DC bus indicates that a DC bus voltage ripple can also induce a big torsional vibration. Next, the study of the closed-loop FOC control method is presented. Simulation for a complete VFD machinery train is performed. With the recti er and DC bus dynamic braking, the system shows a better performance than the ideal-DC bus case. Lastly, a parametric study of the FOC controller is performed. The effects of primary parameters are discussed. The results indicate that some control parameters (i.e. speed ramps, proportional gain in speed PI controller) are also responsible for the mechanical torsional vibration.

Han, Xu

2010-12-01T23:59:59.000Z

39

Empirical Mode Reduction in a Model of Extratropical Low-Frequency Variability  

Science Conference Proceedings (OSTI)

This paper constructs and analyzes a reduced nonlinear stochastic model of extratropical low-frequency variability. To do so, it applies multilevel quadratic regression to the output of a long simulation of a global baroclinic, quasigeostrophic, ...

D. Kondrashov; S. Kravtsov; M. Ghil

2006-07-01T23:59:59.000Z

40

Low-Frequency Variability in a Baroclinic ? Channel with Land–Sea Contrast  

Science Conference Proceedings (OSTI)

Atmospheric low-frequency variability (LFV) is studied in a two-layer quasigeostrophic model. The model geometry is a periodic ? channel with flat bottom and zonally inhomogeneous thermal forcing. As a result of the idealized land–sea contrast, ...

S. Kravtsov; A. W. Robertson; M. Ghil

2003-09-01T23:59:59.000Z

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.


41

Low-Frequency Variability and Remote Forcing of Gap Winds over the East Pacific Warm Pool  

Science Conference Proceedings (OSTI)

The low-frequency variability of gap winds at the Isthmuses of Tehuantepec and Papagayo is investigated using a 17-yr wind stress dataset merging the remotely sensed observations of Special Sensor Microwave Imager (SSM/I) and Quick Scatterometer (...

Kristopher B. Karnauskas; Antonio J. Busalacchi; Raghu Murtugudde

2008-10-01T23:59:59.000Z

42

Stationary Wave Accumulation and the Generation of Low-Frequency Variability on Zonally Varying Flows  

Science Conference Proceedings (OSTI)

A potent mechanism for the generation of low-frequency atmospheric variability on vortex basic states consisting of a single potential vorticity jump, or contour, separating two regions of uniform equivalent barotropic potential vorticity is ...

K. L. Swanson

2000-07-01T23:59:59.000Z

43

Enhanced Recovery Utilizing Variable Frequency Drives and a Distributed Power System  

Science Conference Proceedings (OSTI)

This report describes complete results of the project entitled ''Enhanced Recovery Utilizing Variable Frequency Drives and a Distributed Power System''. This demonstration project was initiated in July 2003 and completed in March 2005. The objective of the project was to develop an integrated power production/variable frequency drive system that could easily be deployed in the oil field that would increase production and decrease operating costs. This report describes all the activities occurred and documents results of the demonstration.

Randy Peden; Sanjiv Shah

2005-07-26T23:59:59.000Z

44

Geographical Variations of the Influence of Low-Frequency Variability on Lower-Tropospheric Extreme Westerly Wind Events  

Science Conference Proceedings (OSTI)

A conceptual framework is developed for quantifying the relationship between low-frequency variability and extreme events. In this framework, variability is decomposed into low-frequency and synoptic components using complementary 10-day low-pass ...

Jeffrey H. Yin; Grant W. Branstator

2008-09-01T23:59:59.000Z

45

Low-Frequency Variability in the Arctic Atmosphere, Sea Ice, and Upper-Ocean Climate System  

Science Conference Proceedings (OSTI)

The low-frequency natural variability of the arctic climate system is modeled using a single-column, energy balance model of the atmosphere. sea ice, and upper-ocean system. Variability in the system is induced by forcing with realistic, random ...

C. M. Bitz; D. S. Battisti; R. E. Moritz; J. A. Beesley

1996-02-01T23:59:59.000Z

46

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

SciTech Connect

Engineers from a government-owned engineering and manufacturing facility were contracted by government-owned research laboratory to design and build an S-band telemetry transmitter using Radio Frequency Integrated Circuit (RFIC) technology packaged 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 and is fabricated by Peregrine Semiconductor corporation. This thesis work details the design of the Voltage Controlled Oscillator (VCO) portion of the PLL frequency synthesizer and constitutes an fully integrated VCO core circuit and a high-isolation buffer amplifier. The high-isolation buffer amplifier was designed to provide 16 dB of gain for 2200-3495 MHz as well as 60 dB of isolation for the oscillator core to provide immunity to frequency pulling due to RF load mismatch. Actual measurements of the amplifier gain and isolation showed the gain was approximately 5 dB lower than the simulated gain when all bond-wire and test substrate parasitics were taken into account. The isolation measurements were shown to be 28 dB at the high end of the frequency band but the measurement was more than likely compromised due to the aforementioned bond-wire and test substrate parasitics. The S-band oscillator discussed in this work was designed to operate over a frequency range of 2200 to 2300 MHz with a minimum output power of 0 dBm with a phase-noise of -92 dBc/Hz at a 100 kHz offset from the carrier. The tuning range was measured to be from 2215 MHz to 2330 MHz with a minimum output power of -7 dBm over the measured frequency range. A phase-noise of -90 dBc was measured at a 100 kHz offset from the carrier.

Garrison, Sean

2009-05-21T23:59:59.000Z

47

Forecast Skill and Low-Frequency Variability in NMC DERF90 Experiments  

Science Conference Proceedings (OSTI)

A series of 90-day integrations by a low-resolution version (T40) of the National Meteorological Center's global spectral model was analyzed for its performance as well as its low-frequency variability behavior. In particular, 5-day mean 500-mb ...

Wilbur Y. Chen; Huug M. van den Dool

1995-08-01T23:59:59.000Z

48

Low-Frequency Pycnocline Depth Variability at Ocean Weather Station P in the Northeast Pacific  

Science Conference Proceedings (OSTI)

Low-frequency variability of the depth of the main pycnocline at Ocean Weather Station P and over the northeast Pacific is examined in terms of the one-dimensional response to local Ekman pumping according to the Hasselmann stochastic climate ...

Patrick F. Cummins; Gary S. E. Lagerloef

2002-11-01T23:59:59.000Z

49

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

Science Conference Proceedings (OSTI)

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

50

Low-Frequency Variability in the Northern Hemisphere Winter: Geographical Distribution, Structure and Time-Scale Dependence  

Science Conference Proceedings (OSTI)

Low-frequency variability in wintertime 500 mb height is examined, with emphasis on its structure, geographical distribution, and frequency dependence. A 39-year record of 500 mb geopotential height fields from the NMC analyses is time filtered ...

Yochanan Kushnir; John M. Wallace

1989-10-01T23:59:59.000Z

51

The Role of Pacific Climate on Low-Frequency Hydroclimatic Variability and Predictability in Southern Alberta, Canada  

Science Conference Proceedings (OSTI)

Wavelet and rank correlation analysis were used to identify the links between primary Pacific climate variability modes and low-frequency hydroclimatic variability in the South Saskatchewan River basin (SSRB) of southern Alberta. The April–...

Adam K. Gobena; Thian Y. Gan

2009-12-01T23:59:59.000Z

52

CMOS implementation of a 1.6 GHz low voltage low phase noise quadrature output frequency synthesizer with automatic amplitude control  

Science Conference Proceedings (OSTI)

This article presents the design of a 1.2 V CMOS low phase noise quadrature output frequency synthesizer (FS) to be used for a GPS tuner application. Special reference is made to the design of a wide tuning range quadrature output voltage-controlled ... Keywords: AM-to-PM up-conversion, Automatic amplitude control, DC---DC Converter, Phase noise, Quadrature VCO

Owen Casha; Ivan Grech; Joseph Micallef; Edward Gatt

2008-04-01T23:59:59.000Z

53

Model of variable speed constant frequency double fed wind power generation system and analysis of its operating performance  

Science Conference Proceedings (OSTI)

Structure of variable speed constant frequency double fed wind power generation system (WPGS) was analyzed, and its model was established. Maximum power point tracking (MPPT) control, constant power control and vector control for WPGS were discussed. ... Keywords: operating performance, variable speed constant frequency, vector control, wind power generation system

Pan Tinglong; Ji Zhicheng

2009-06-01T23:59:59.000Z

54

Power links with Ireland -- Excitation of turbine-generator shaft torsional vibrations by variable frequency currents superimposed on DC currents in asynchronous HVDC links  

Science Conference Proceedings (OSTI)

The paper describes an in-depth analysis of 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 the DC currents in asynchronous Links. It extends earlier work to include an in depth analysis of system scaling factors for harmonic currents impressed on generators in Northern Ireland by an inverter and to investigate the phenomena for possible torsional vibrations in the generators by the Link. Frequencies at which shaft torsional vibrations would be excited by modulation product harmonics in 50Hz/50Hz asynchronous Links as a function of deviation in system frequency is reviewed. Relative noncharacteristic current levels for 50Hz/50Hz connectors are illustrated assuming ripple currents at the inverter which gives realistic harmonic voltages in a twelve-pulse bridge. The paper then shows that torques in machines in multi-machine networks may be estimated by proportioning HVDC link harmonic disturbance current appropriately to each machine at risk. It is concluded that variable-frequency ripple currents superimposed on the DC current in asynchronous links can excite sympathetic torsional vibrations in turbine-generator-exciter shafts.

Hammons, T.J.; Tay, B.W.; Kok, K.L. [Glasgow Univ. (United Kingdom)

1995-08-01T23:59:59.000Z

55

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

56

Impact of Atmospheric Intraseasonal Variability in the Indian Ocean: Low-Frequency Rectification in Equatorial Surface Current and Transport  

Science Conference Proceedings (OSTI)

An ocean general circulation model (OGCM) is used to investigate the low-frequency (period longer than 90 days) rectification of atmospheric intraseasonal variability (10–90-day periods) in zonal surface current and transport of the equatorial ...

Weiqing Han; Peter Webster; Roger Lukas; Peter Hacker; Aixue Hu

2004-06-01T23:59:59.000Z

57

Phenomenology of the Low-Frequency Variability in a Reduced-Gravity, Quasigeostrophic Double-Gyre Model  

Science Conference Proceedings (OSTI)

The low-frequency variability of the oceanic wind-driven circulation is investigated by use of a reduced-gravity, quasigeostrophic model with slight variations on the classic double-gyre wind forcing. Approximately 30 eddy-resolving simulations ...

John D. McCalpin; Dale B. Haidvogel

1996-05-01T23:59:59.000Z

58

Structure of Oceanic and Atmospheric Low-Frequency Variability over the Tropical Pacific and Indian Oceans. Part I: COADS Observations  

Science Conference Proceedings (OSTI)

The recurrent modes of combined oceanic and atmospheric low-frequency variability over the tropical Pacific and Indian oceans are calculated to provide quantitatively and structurally well-defined targets for simulation/prediction studies of ...

Sumant Nigam; Horng-Syi Shen

1993-04-01T23:59:59.000Z

59

Observations and EOF Analysis of Low-Frequency Variability in the Western Part of the Gulf Stream Recirculation  

Science Conference Proceedings (OSTI)

This study of low-frequency oceanic variability is based on data collected during the Long Term Upper Ocean Study (LOTUS), which was a two year program of (mainly) moored meteorological and oceanographic measurements. The mooring arrays were ...

Angelika Lippert; Melbourne G. Briscoe

1990-05-01T23:59:59.000Z

60

Contributions of ENSO and East Indian Ocean SSTA to the Interannual Variability of Northwest Pacific Tropical Cyclone Frequency  

Science Conference Proceedings (OSTI)

This study attempts to understand contributions of ENSO and the boreal summer sea surface temperature anomaly (SSTA) in the East Indian Ocean (EIO) to the interannual variability of tropical cyclone (TC) frequency over the western North Pacific (...

Ruifen Zhan; Yuqing Wang; Xiaotu Lei

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.


61

Reconstruction of the Extratropical NH Mean Temperature over the Last Millennium with a Method that Preserves Low-Frequency Variability  

Science Conference Proceedings (OSTI)

A new multiproxy reconstruction of the Northern Hemisphere extratropical mean temperature over the last millennium is presented. The reconstruction is performed with a novel method designed to avoid the underestimation of low-frequency variability ...

Bo Christiansen; Fredrik Charpentier Ljungqvist

2011-12-01T23:59:59.000Z

62

Dynamics and Practical Predictability of Extratropical Wintertime Low-Frequency Variability in a Low-Dimensional System  

Science Conference Proceedings (OSTI)

Dynamics and practical predictability of extratropical low-frequency variability (LFV) in Northern Hemisphere winter are examined in the framework of a two-dimensional (2D) stochastic differential equation (SDE) on the phase space spanned by two ...

Masaru Inatsu; Naoto Nakano; Hitoshi Mukougawa

2013-03-01T23:59:59.000Z

63

On Robust Estimation of Low-Frequency Variability Trends in Discrete Markovian Sequences of Atmospheric Circulation Patterns  

Science Conference Proceedings (OSTI)

Identification and analysis of temporal trends and low-frequency variability in discrete time series is an important practical topic in the understanding and prediction of many atmospheric processes, for example, in analysis of climate change. ...

Illia Horenko

2009-07-01T23:59:59.000Z

64

Low-frequency variability of currents in the deepwater eastern Gulf of Mexico  

E-Print Network (OSTI)

Vertical structure of the low frequency horizontal currents at the northern edge of the Loop Current during eddy shedding events is observed using concurrent hydrographic, moored, and satellite altimetry data from 2005. Dynamic modes are calculated at three deep (~3000 m), full water-column moorings in the eastern Gulf of Mexico. Time-series of the barotropic and first two baroclinic modes are found using a least squares minimization that fits theoretically derived modes to observed moored velocity data. EOF analyses show that the majority of observed variance is explained by a surface-trapped mode that is highly coherent with the temporal amplitudes of the first baroclinic mode, and a lower, but significant percentage of variance is captured in bottom-intensified modes. Amplitudes of the second empirical mode indicate that currents are more coherent in the ocean interior approaching the Loop Current, as more variance is explained by this mode at the southernmost mooring near the Loop Current. A dynamic mode decomposition of the horizontal currents reveals that the barotropic and first baroclinic modes exhibit low frequency variability and eddy time scales of 10 – 40 days. Second baroclinic mode amplitudes show higher frequency variability 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 to the model when cyclonic features are present in the study area. The importance of the second baroclinic mode to the model increases significantly closer to the Loop Current. High-speed currents associated with the Loop Current and anticyclones stimulate a strong first baroclinic response, but the second baroclinic mode amplitudes are found to be similar in magnitude to the first baroclinic mode amplitudes at times. This happens episodically and could be an indication of higher order dynamics related to frontal eddies or Loop Current eddy shedding.

Cole, Kelly Lynne

2008-08-01T23:59:59.000Z

65

The frequency and voltage dependent electrical characteristics of Al-TiW-Pd2Si/n-Si structure using I-V, C-V and G/?-V measurements  

Science Conference Proceedings (OSTI)

The forward and reverse bias capacitance-voltage (C-V) and conductance-voltage (G/w-V) characteristics of Al-TiW-Pd"2Si/n-Si structures have been investigated over a wide frequency range of 5kHz-5MHz. These measurements allow to us the determination ... Keywords: 73.30.+y, 73.40.Ns, 73.40.Qv, Frequency dependent, Interface states, MS structure, Pd2Si/n-Si contacts, Series resistance

?. M. Afandiyeva; ?. Dökme; ?. Alt?ndal; L. K. Abdullayeva; Sh. G. Askerov

2008-02-01T23:59:59.000Z

66

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

67

Optical voltage reference  

DOE Patents (OSTI)

An optical voltage reference for providing an alternative to a battery source. 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.

Rankin, R.; Kotter, D.

1992-12-31T23:59:59.000Z

68

Low Wind Speed Technology Phase II: Investigation of the Application of Medium-Voltage Variable-Speed Drive Technology to Improve the Cost of Energy from Low Wind Speed Turbines; Behnke, Erdman and Whitaker Engineering, Inc.  

SciTech Connect

This fact sheet describes a subcontract with Behnke, Erdman & Whitaker Engineering, Inc. to test the feasibility of applying medium-voltage variable-speed drive technology to low wind speed turbines.

2006-03-01T23:59:59.000Z

69

Transverse electric conductivity and dielectric permeability in quantum degenerate collisional plasma with variable collision frequency in Mermin's approach  

E-Print Network (OSTI)

Formulas for transverse conductance and dielectric permeability in quantum degenerate collisional plasma with arbitrary variable collision frequency in Mermin's approach are deduced. Frequency of collisions of particles depends arbitrarily on a wave vector. For this purpose the kinetic Shr\\"{o}dinger - Boltzmann equation with collision integral of relaxation type in momentum space is applied. The case of degenerate Fermi plasma is allocated and investigated. The special case of frequency of collisions proportional to the module of a wave vector is considered. The graphic analysis of the real and imaginary parts of dielectric function is made.

Latyshev, A V

2013-01-01T23:59:59.000Z

70

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

71

FPGA Implementation of Space Vector PWM Technique for Voltage Source Inverter Fed Induction Motor Drive  

Science Conference Proceedings (OSTI)

This paper presents implementation of Space Vector Pulse Width Modulation (SVPWM) technique for three phase Voltage Source Inverter (VSI) using Field Programmable Gate Array (FPGA). Variable voltage and frequency supply to ac drives is invariably obtained ... Keywords: VSI, SVPWM, FPGA, Induction Motor

R. Rajendran; N. Devarajan

2009-12-01T23:59:59.000Z

72

Experimental Analysis of Variable Capacity Heat Pump Systems equipped with a liquid-cooled frequency inverter.  

E-Print Network (OSTI)

?? Using an inverter-driven compressor in variable capacity heat pump systems has a main drawback, which is the extra loss in the inverter. The present… (more)

Ebraheem, Thair

2013-01-01T23:59:59.000Z

73

A Minimal Baroclinic Model for the Statistical Properties of Low-Frequency Variability  

Science Conference Proceedings (OSTI)

A recent analysis of atmospheric observations has shown evidence of bimodality in the statistical distribution of wave amplitude in the ultralong (zonal wavenumber group 2–4), low frequency (period >5 days). Similar analysis of the zonal wind and ...

R. Benzi; A. Speranza; A. Sutera

1986-12-01T23:59:59.000Z

74

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

Science Conference Proceedings (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

75

A Linear Model of Wintertime Low-Frequency Variability. Part I: Formulation and Forecast Skill  

Science Conference Proceedings (OSTI)

A linear inverse model (LIM) suitable for studies of atmospheric extratropical variability on longer than weekly timescales is constructed using observations of the past 30 years. Notably, it includes tropical diabatic heating as an evolving ...

Christopher R. Winkler; Matthew Newman; Prashant D. Sardeshmukh

2001-12-01T23:59:59.000Z

76

Dynamical Origin of Low-Frequency Variability in a Highly Nonlinear Midlatitude Coupled Model  

Science Conference Proceedings (OSTI)

A novel mechanism of decadal midlatitude coupled variability, which crucially depends on the nonlinear dynamics of both the atmosphere and the ocean, is presented. The coupled model studied involves quasigeostrophic atmospheric and oceanic ...

S. Kravtsov; P. Berloff; W. K. Dewar; M. Ghil; J. C. McWilliams

2006-12-01T23:59:59.000Z

77

North Atlantic modeling of low-frequency variability in mode water formation  

E-Print Network (OSTI)

The generation of interannual and near-decadal variability in the formation of mode waters in the western North Atlantic is investigated in the realistic framework of an isopycnic coordinate ocean model forced with atmospheric data from 1946 to 1988. At Bermuda, the model reproduces quite well the observed potential vorticity and isopycnal depth anomalies associated with the subtropical mode water (STMW). Heat storage and preconditioning of the convective activity are found to be the important factors for the generation of STMW variability, with persistence of cold (warm) conditions, associated with anomalous heat loss (gain) over the western subtropics, being more significant for the generation of the simulated variability than are strong anomalous events in isolated years. In the Labrador Sea, the model captures the phase and order of magnitude of the observed near-decadal variability in the convective activity, if not its maximum amplitude. The simulated potential vorticity anomali...

Afonso M. Paiva; Eric P. Chassignet

2001-01-01T23:59:59.000Z

78

Evaporation-Wind Feedback and Low-Frequency Variability in the Tropical Atmosphere  

Science Conference Proceedings (OSTI)

A mechanism by which feedback between zonal wind perturbations and evaporation can create unstable, low-frequency modes in a simple two-layer model of the tropical troposphere is presented. The modes resemble the 30–50 day oscillation. A series ...

J. David Neelin; Isaac M. Held; Kerry H. Cook

1987-08-01T23:59:59.000Z

79

Summer Severe-Rainfall Frequency Trend and Variability over Ontario, Canada  

Science Conference Proceedings (OSTI)

During the last two decades (1979–2002), there has been an ever-increasing frequency of summer severe-rainfall events over Ontario, Canada. This observed upward trend is robust as demonstrated through the Mann–Kendall test with consideration of ...

Zuohao Cao; Jianmin Ma

2009-09-01T23:59:59.000Z

80

Ocean Model Diagnosis of Low-Frequency Climate Variability in the South Atlantic Region  

Science Conference Proceedings (OSTI)

South Atlantic Ocean variability is investigated by means of an ocean general circulation model (ORCA2), forced with the NCEP–NCAR reanalyses for the 1948–99 period. A rotated EOF analysis of the mixed layer temperature suggests a breakdown of ...

Frank Colberg; C. J. C. Reason

2007-03-01T23:59:59.000Z

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

The Influence of Midlatitude Ocean–Atmosphere Coupling on the Low-Frequency Variability of a GCM. Part I: No Tropical SST Forcing  

Science Conference Proceedings (OSTI)

This study examines the extent to which the thermodynamic interactions between the midlatitude atmosphere and the underlying oceanic mixed layer contribute to the low-frequency atmospheric variability. A general circulation model, run under ...

Ileana Bladé

1997-08-01T23:59:59.000Z

82

The Ocean Response to Low-Frequency Interannual Atmospheric Variability in the Mediterranean Sea. Part I: Sensitivity Experiments and Energy Analysis  

Science Conference Proceedings (OSTI)

In this study a general circulation model is used in order to investigate the interannual response of the Mediterranean Basin to low-frequency interannual variability in atmospheric forcing for the period 1980–88. The model incorporates a ...

G. Korres; N. Pinardi; A. Lascaratos

2000-02-01T23:59:59.000Z

83

A Qualitatively Realistic Low-Order Model of the Extratropical Low-Frequency Variability Built from Long Records of Potential Vorticity  

Science Conference Proceedings (OSTI)

A low-order deterministic qualitative model is formulated in order to simulate extratropical low-frequency variability. This deterministic model is based on a filtering of the potential vorticity equation on the 315-K isentrope and a projection ...

Eduardo Da Costa; Robert Vautard

1997-04-01T23:59:59.000Z

84

Transverse electric conductivity and dielectric permeability in quantum non-degenerate and maxwellian collisional plasma with variable collision frequency in Mermin's approach  

E-Print Network (OSTI)

Formulas for transverse conductance and dielectric permeability in quantum non-degenerate and Maxwellian collisional plasma with arbitrary variable collision frequency in Mermin's approach are deduced. Frequency of collisions of particles depends arbitrarily on a wave vector. The special case of frequency of collisions proportional to the module of a wave vector is considered. The graphic analysis of the real and imaginary parts of dielectric function is made.

Latyshev, A V

2013-01-01T23:59:59.000Z

85

Low Wind Speed Turbine Project Phase II: The Application of Medium-Voltage Electrical Apparatus to the Class of Variable Speed Multi-Megawatt Low Wind Speed Turbines; 15 June 2004--30 April 2005  

DOE Green Energy (OSTI)

Kilowatt ratings of modern wind turbines have progressed rapidly from 50 kW to 1,800 kW over the past 25 years, with 3.0- to 7.5-MW turbines expected in the next 5 years. The premise of this study is simple: The rapid growth of wind turbine power ratings and the corresponding growth in turbine electrical generation systems and associated controls are quickly making low-voltage (LV) electrical design approaches cost-ineffective. This report provides design detail and compares the cost of energy (COE) between commercial LV-class wind power machines and emerging medium-voltage (MV)-class multi-megawatt wind technology. The key finding is that a 2.5% reduction in the COE can be achieved by moving from LV to MV systems. This is a conservative estimate, with a 3% to 3.5% reduction believed to be attainable once purchase orders to support a 250-turbine/year production level are placed. This evaluation considers capital costs as well as installation, maintenance, and training requirements for wind turbine maintenance personnel. Subsystems investigated include the generator, pendant cables, variable-speed converter, and padmount transformer with switchgear. Both current-source and voltage-source converter/inverter MV topologies are compared against their low-voltage, voltage-source counterparts at the 3.0-, 5.0-, and 7.5-MW levels.

Erdman, W.; Behnke, M.

2005-11-01T23:59:59.000Z

86

? Adjustable Output Voltage  

E-Print Network (OSTI)

The LM25010 features all the functions needed to implement a low cost, efficient, buck regulator capable of supplying in excess of 1A load current. This high voltage regulator integrates an N-Channel Buck Switch, and is available in thermally enhanced LLP-10 and TSSOP-14EP packages. The constant on-time regulation scheme requires no loop compensation resulting in fast load transient response and simplified circuit implementation. The operating frequency remains constant with line and load variations due to the inverse relationship between the input voltage and the on-time. The valley current limit detection is set at 1.25A. Additional features include: VCC under-voltage lock-out, thermal shutdown, gate drive under-voltage lock-out, and maximum duty cycle limiter.

Lmq Is Aec-q Grade

2008-01-01T23:59:59.000Z

87

A Framework of Concurrent Task Scheduling and Dynamic Voltage and Frequency Scaling in Real-Time Embedded Systems with Energy Harvesting  

E-Print Network (OSTI)

harvesting module is comprised of a Photovoltaic (PV) panel for harvesting energy and a supercapacitor panel, state-of- charge management for the supercapacitor, and energy-harvesting- aware real-time task-leakage of the supercapacitor, and power losses in voltage converters, employs a cascaded feedback control structure

Pedram, Massoud

88

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.

Mikesell, Harvey E. (McMurray, PA); Lucy, Eric (Murrysville, PA)

1998-01-01T23:59:59.000Z

89

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

90

Technology Assessment and Application Guide for the Bonitron Single-Phase Power Supply for Three-Phase Variable Frequency Drives  

Science Conference Proceedings (OSTI)

The objective of this report is to describe and document the operation and performance of a Bonitron single-phase power supply that is designed to allow three-phase drive operation. This report will describe the different tests that were conducted to characterize the Bonitron power supply and their results. The tests that were conducted include voltage sag, interruption, recloser, and harmonic profiling. Additional characterization tests are also discussed.The voltage sag and ...

2013-10-17T23:59:59.000Z

91

Low-Frequency Variability, Coherence Resonance, and Phase Selection in a Low-Order Model of the Wind-Driven Ocean Circulation  

Science Conference Proceedings (OSTI)

In this paper, a low-order spectral quasigeostrophic (QG) model of the wind-driven ocean circulation is derived and used to analyze the low-order character of the intrinsic low-frequency variability of the midlatitude double-gyre ocean circulation ...

Stefano Pierini

2011-09-01T23:59:59.000Z

92

Comparison on control strategies of the grid-side converter of variable speed constant frequency doubly-fed wind power generation system  

Science Conference Proceedings (OSTI)

Direct power control, vector control based on d-q synchronous rotating reference frame and ?-? static reference frame for the grid-side converter of variable speed constant frequency doubly-fed wind turbines are analyzed. System simulation ... Keywords: ?-? static reference frame, d-q rotating reference frame, direct power control, doubly-fed wind power generation system, grid-side converter

Xian-Ming Zhou; Ting-Long Pan; Zhi-Cheng Ji

2009-06-01T23:59:59.000Z

93

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) for typical fan and pump loads. It also discusses advantages and disadvantages of using mechanical MC-ASD versus VFDs and it provides field experience with VFDs in refrigerated warehouses as well as the fixed magnet MC-ASD in wastewater and other field applications. Laboratory tests for a 50 hp fan retrofit showed electronic VFD savings at 62%, the MagnaDrive Coupling at 39% and PAYBACK Drive at 46%. At $0.06/kWh and list prices, the simple payback for the VFD is 2.4 years, the MagnaDrive is 4.6 years and the PAYBACK is 1.9 years. MagnaDrive has models from 25 to 500 hp while PAYBACK has models from 3 to 200 hp. Contractors to the Northwest Energy Efficiency Alliance have helped to install VFDs for about 300 evaporator fans in over two dozen refrigerated warehouses and to install fixed-magnet MC-ASDs in about 50 applications with about half of these controlling wastewater pumps. The Alliance has no particular field experience with the electcromagnetic coupling. The primary advantages of magnetically coupled adjustable speed drives (MC-ASD) over VFDs come from reduced maintenance, resistance to dirty environments, separation of load vibration from the motor, and less stringent requirements for precise shaft alignment. Field experience indicates reductions in noise and repairs from vibration loads, tolerance of poor electrical power quality, and ease of installation are often more important than energy savings. The MC-ASDs are being used where VFDs have not survived or are considered too complicated.

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

2003-05-01T23:59:59.000Z

94

Radio Frequency Engineering, MDE, Accelerator Operations and...  

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

Home Teams Low-Level Radio Frequency Magnet Power Supplies, Pulsed Power Radio Frequency, High Voltage Technologies Radio Frequency Operations CONTACTS Group Leader Dan Rees Deputy...

95

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

E-Print Network (OSTI)

nation’s mix of generation sources changes. The potentiallarge conventional generation sources can be used as a toolVariable Renewable Generation Source: Undrill (2010) Figure

Eto, Joseph H.

2011-01-01T23:59:59.000Z

96

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

E-Print Network (OSTI)

Integration of Variable Renewable Generation The report isISO (CAISO). 2007. Integration of Renewable Resources.recommendations for integrating renewable resources on the

Eto, Joseph H.

2011-01-01T23:59:59.000Z

97

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

E-Print Network (OSTI)

control because the industry assumed that power system operationsPower system operations planners conduct extensive studies to assess whether primary frequency controlcontrol is a fundamental requirement for reliable operation of any power system.

Eto, Joseph H.

2011-01-01T23:59:59.000Z

98

Climate Variability and the Frequency of Extreme Temperature Events for Nine Sites across Canada: Implications for Power Usage  

Science Conference Proceedings (OSTI)

To study the impact of incremental climatic warming on summer extreme temperature event frequency, the historical record of daily maximum June, July, and August temperatures was analyzed for nine sites across Canada. It was found that all of ...

Andrew F. Colombo; David Etkin; Bryan W. Karney

1999-08-01T23:59:59.000Z

99

Seasonal and Low-Frequency Variability of the Meridional Heat Flux at 36°N in the North Atlantic  

Science Conference Proceedings (OSTI)

Historical hydrographic sections are used to investigate the seasonal and interannual variability in the meridional heat flux at 36°N in the North Atlantic. The data consist of ten transatlantic sections and sections from four sectors, which ...

Olga T. Sato; T. Rossby

2000-03-01T23:59:59.000Z

100

Low-Frequency Variability of the Equatorial Pacific Ocean Using a New Pseudostress Dataset: 1930–1989  

Science Conference Proceedings (OSTI)

Interannual and interdecadal variability of the equatorial Pacific are examined using a new pseudostress dataset. The monthly mean pseudostress fields (1930–89)are derived from Comprehensive Ocean-Atmosphere Data Set (COADS) pseudostresses using ...

Jay F. Shriver; James J. O'Brien

1995-11-01T23:59:59.000Z

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

Longitudinal electric conductivity and dielectric permeability in quantum plasma with variable frequency of collisions in Mermin' approach  

E-Print Network (OSTI)

Formulas for longitudinal electric conductivity and dielectric permeability in the quantum non-degenerate collisional plasma with the frequency of collisions depending on momentum in Mermin' approach are received. The kinetic equation in momentum space in relaxation approximation is used. It is shown that when Planck's constant tends to zero, the deduced formula passes to the corresponding formula for classical plasma. It is shown also that when frequency of collisions of particles of plasma tends to zero (plasma passes to collisionless one), the deduced formula passes to the known Lindhard' formula received for collisionless plasmas. It is shown, that when frequency of collisions is a constant, the deduced formula for dielectric permeability passes in known Mermin' formula.

A. V. Latyshev; A. A. Yushkanov

2012-12-22T23:59:59.000Z

102

Longitudinal electric conductivity and dielectric permeability in quantum plasma with variable frequency of collisions in Mermin' approach  

E-Print Network (OSTI)

Formulas for longitudinal electric conductivity and dielectric permeability in the quantum non-degenerate collisional plasma with the frequency of collisions depending on momentum in Mermin' approach are received. The kinetic equation in momentum space in relaxation approximation is used. It is shown that when Planck's constant tends to zero, the deduced formula passes to the corresponding formula for classical plasma. It is shown also that when frequency of collisions of particles of plasma tends to zero (plasma passes to collisionless one), the deduced formula passes to the known Lindhard' formula received for collisionless plasmas. It is shown, that when frequency of collisions is a constant, the deduced formula for dielectric permeability passes in known Mermin' formula.

Latyshev, A V

2012-01-01T23:59:59.000Z

103

Time-Frequency Analysis of GALLEX and GNO Solar Neutrino Data: Evidence Suggestive of Asymmetric and Variable Nuclear Burning  

E-Print Network (OSTI)

Time-frequency analysis of data from the GALLEX and GNO solar neutrino experiments shows that some features in power-spectrum analyses of those datasets are due to aliasing. We normalize data for each of the four experiments in the GALLEX series, concatenate the resulting normalized data, and then form time-frequency displays. We also form time-frequency displays of the two principal modulations found in the data, at 11.87 yr-1 and at 13.63 yr-1, and of the datasets formed by subtracting these modulations from the actual (normalized) data. The results suggest that the true modulation is that at 11.87 yr-1, consistent with the results of our earlier analysis of Homestake solar neutrino data. Comparison with helioseismology data indicates that modulation is occurring either in the radiative zone just below the tachocline, presumably by the RSFP (resonant spin-flavor precession) process, or in the core, presumably due to inhomogeneities and fluctuations in the nuclear-burning process.

P. A. Sturrock

2008-02-22T23:59:59.000Z

104

Fourier decomposition and frequency analysis of the pulsating stars with PRRc and RRab variables. Separation criteria and particularities  

E-Print Network (OSTI)

The OGLE database is revisited to investigate in more detail the properties of the Fourier parameters. Methodological improvements led us to identify a clear separation among High-Amplitude Delta Scuti (HADS), RRc and RRab stars. The bimodal distribution of the R21 parameter in HADS stars is explained as a contamination effect from RRc stars: there is evidence that all stars with 0.20RRc variables. The previously claimed existence of a subclass of unusual HADS is demonstrated to be a spurious result. Candidate overtone pulsators are found among HADS and RRc variables. The properties of the Fourier parameters are discussed as a function of the physical conditions in the stars involved. Among the field RRab stars we detected different light-curve groups producing distinct "tails" in the Fourier plots for P>0.55 d; evolutionary phases or the combination of different physical conditions (not only metallicity) are suggested to explain this separation, observed also in the cluster RRab stars. The stellar parameters of RRc stars in a given globular cluster show different tendencies than those of RRc stars from different clusters.

Ennio Poretti

2001-03-29T23:59:59.000Z

105

Stressing of turbine-generator-exciter shafts by variable-frequency currents superimposed on DC currents in asynchronous HVDC links and following disturbances at converter stations  

SciTech Connect

Ripple currents on the DC side of both HVDC synchronous and asynchronous. Links together with cleared HVDC and AC system disturbances 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, and because AC/DC/AC couplers are to be installed extensively to interconnect the East and West European Grid Systems. This paper discusses and analyses excitation of shaft torsional vibrations in steam turbine-generator-exciter shafts in close proximity to HVDC converter stations by (1) variable-frequency ripple currents superimposed on the DC currents in asynchronous Links, and (2) disturbances at bi-polar converter stations. The time response and tables show that for the systems studied variable-frequency ripple currents superimposed on the DC current in asynchronous Links can excite shaft torsional vibrations, the very small noncharacteristic currents could result in onerous shaft torques which might damage the machine, and that DC line faults at converter stations in close proximity of steam turbine-generator units can excite onerous turbine-generator shaft torsional response. Detailed simulation of the HVDC converter and generator is necessary for precise assessments of shaft torsional response following HVDC converter station faults. 500MW, 660MW, 1000MW and 1300MW machines are considered in the analyses that are made.

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

1994-09-01T23:59:59.000Z

106

PQ Encyclopedia: Understanding Voltage Unbalance  

Science Conference Proceedings (OSTI)

This PQ Encyclopedia examines voltage unbalance, methods to calculate line voltages and the degree of voltage unbalance, and mitigation techniques.

2009-12-11T23:59:59.000Z

107

Demonstration of Commissioning Tests for Extra-High Voltage Cross-Linked Polyethylene Cable Systems at Los Angeles Department of Wat er and Power  

Science Conference Proceedings (OSTI)

Today, utilities are installing an increasing number of cross-linked polyethylene (XLPE) transmission cables with system voltages ranging from 115 kV up to 345 kV. This report summarizes field partial discharge measurements and high-voltage ac commissioning tests performed on a Los Angeles Department of Water and Power (LADWP) 230-kV XLPE transmission cable system. The commissioning tests were performed with a field transportable, variable frequency, series resonant test set at 1.4 times rated voltage.

2002-09-11T23:59:59.000Z

108

HIGH VOLTAGE GENERATOR  

DOE Patents (OSTI)

This patent relates to high voltage supply circuits adapted for providing operating voltages for GeigerMueller counter tubes, and is especially directed to an arrangement for maintaining uniform voltage under changing conditions of operation. In the usual power supply arrangement for counter tubes the counter voltage is taken from across the power supply output capacitor. If the count rate exceeds the current delivering capaciiy of the capacitor, the capacitor voltage will drop, decreasing the counter voltage. The present invention provides a multivibrator which has its output voltage controlled by a signal proportional to the counting rate. As the counting rate increases beyond the current delivering capacity of the capacitor, the rectified voltage output from the multivibrator is increased to maintain uniform counter voltage.

Zito, G.V.

1959-04-21T23:59:59.000Z

109

Mitigation of different type voltage sags in low voltage distribution systems using dynamic voltage restorer  

Science Conference Proceedings (OSTI)

The main problems of the voltage sag in low voltage distribution systems due to sensitive loads. Voltage sags can caused malfunction in the distribution system. In order to protect voltage sags in the network a device which called Dynamic Voltage Restorer ... Keywords: custom device, dynamic voltage restorer (DVR), low voltage, power injected, voltage sag

Rosli Omar

2010-03-01T23:59:59.000Z

110

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

Science Conference Proceedings (OSTI)

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)

1995-03-01T23:59:59.000Z

111

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

112

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

113

Constant voltage ultracapacitor  

Science Conference Proceedings (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

Ezzat G. Bakhoum

2012-01-01T23:59:59.000Z

114

Research on Low-Voltage Ride-Through Technology of Doubly-Fed VSCF Wind Power Generation System  

Science Conference Proceedings (OSTI)

Currently, some of the variable speed wind turbine on market have some low-voltage through capacity?LVRT?, but do not have dynamic reactive power support capacity under fault. DFIG can’t provide dynamic voltage support, in addition, ... Keywords: wind power, voltage dip, low voltage ride-through (LVRT), transient voltage control, rotor-side converter

Bao Wei; Yin Zhongdong

2009-10-01T23:59:59.000Z

115

Automated Voltage Standard Ready  

Science Conference Proceedings (OSTI)

... “We wanted a standard that was ... as envisioned, then within our lifetimes there will no longer be a need for voltage transfer standards that have to be ...

2013-04-08T23:59:59.000Z

116

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

117

A low-noise bandgap voltage reference employing dynamic element matching  

E-Print Network (OSTI)

Bandgap voltages references are widely used in IC design, but are sensitive to low-frequency noise and component mismatch. This thesis describes the design and testing of a new IC voltage reference that targets these issues ...

Herbst, Steven (Steven G.)

2011-01-01T23:59:59.000Z

118

Relationships between Systematic Errors in Medium Range Numerical Forecasts and Some of the Principal Modes of Low-Frequency Variability of the Northern Hemisphere 700 mb Circulation  

Science Conference Proceedings (OSTI)

The relationship between the existence of low-frequency 700 mb height anomalies in the initial conditions of NMC's MRF global spectral model and subsequent 5-, 7-, and 10-day forecasts of 700 mb height from 1982 to 1988 is explored. Low-frequency ...

Edward A. O'Lenic; Robert E. Livezey

1989-06-01T23:59:59.000Z

119

Voltage Quality Improvement Using DVR  

Science Conference Proceedings (OSTI)

The problem of voltage sags and Swells and its severe impact on sensitive loads is well known. To solve this problem, custom power devices are used. One of those devices is the Dynamic Voltage Restorer (DVR), which is one of the most efficient and effective ... Keywords: Dynamic Voltage Restorer (DVR), Voltage sags, Voltage swells, Custom power, Power Quality

M. Arun Bhaskar; S. S. Dash; C. Subramani; M. Jagadeesh Kumar; P. R. Giresh; M. Varun Kumar

2010-03-01T23:59:59.000Z

120

Voltage balanced multilevel voltage source converter system  

SciTech Connect

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

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

Voltage balanced multilevel voltage source converter system  

SciTech Connect

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

122

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

123

Current-Voltage and Capacitance-Voltage characteristics of Pd ...  

Science Conference Proceedings (OSTI)

Presentation Title, Current-Voltage and Capacitance-Voltage characteristics of Pd ... Nonlocal Modeling in High Rate Deformation and Ductile Fracture of ...

124

Low-Frequency Variability of Temperature in the Vicinity of the Equatorial Pacific Thermocline in SODA: Role of Equatorial Wave Dynamics and ENSO Asymmetry  

Science Conference Proceedings (OSTI)

The Simple Ocean Data Assimilation (SODA) reanalysis (1958–2001) is used to investigate the decadal variability in the equatorial thermocline in the Pacific. Whereas the thermocline depth exhibits weak variation at decadal time scales, the ...

B. Dewitte; S. Thual; S-W. Yeh; S-I. An; B-K. Moon; B. S. Giese

2009-11-01T23:59:59.000Z

125

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

126

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

127

Comparative High Voltage Impulse Measurement  

Science Conference Proceedings (OSTI)

... substrate and surrounded by insulating oil; the low ... the amplitudes of the voltage peaks that are ... The uncertainties in the peak output voltages for the ...

2013-04-19T23:59:59.000Z

128

Device for monitoring cell voltage  

SciTech Connect

A device for monitoring a rechargeable battery having a number of electrically connected cells includes at least one current interruption switch for interrupting current flowing through at least one associated cell and a plurality of monitoring units for detecting cell voltage. Each monitoring unit is associated with a single cell and includes a reference voltage unit for producing a defined reference threshold voltage and a voltage comparison unit for comparing the reference threshold voltage with a partial cell voltage of the associated cell. The reference voltage unit is electrically supplied from the cell voltage of the associated cell. The voltage comparison unit is coupled to the at least one current interruption switch for interrupting the current of at least the current flowing through the associated cell, with a defined minimum difference between the reference threshold voltage and the partial cell voltage.

Doepke, Matthias (Garbsen, DE); Eisermann, Henning (Edermissen, DE)

2012-08-21T23:59:59.000Z

129

Electron launching voltage monitor  

DOE Patents (OSTI)

An electron launching voltage monitor measures MITL voltage using a relationship between anode electric field and electron current launched from a cathode-mounted perturbation. An electron launching probe extends through and is spaced from the edge of an opening in a first MITL conductor, one end of the launching probe being in the gap between the MITL conductor, the other end being adjacent a first side of the first conductor away from the second conductor. A housing surrounds the launching probe and electrically connects the first side of the first conductor to the other end of the launching probe. A detector detects the current passing through the housing to the launching probe, the detected current being representative of the voltage between the conductors.

Mendel, Clifford W. (Albuquerque, NM); Savage, Mark E. (Albuquerque, NM)

1992-01-01T23:59:59.000Z

130

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

131

A high-voltage low-power DC-DC buck regulator for automotive applications  

Science Conference Proceedings (OSTI)

This work presents a High-Voltage Low-Power CMOS DC-DC buck regulator for automotive applications. The overall system, including the high and low voltage analog devices, the power MOS and the low voltage digital devices, was realized in the Austriamicrosystems ... Keywords: DC-DC regulator, buck converter, current control, low quiscent current, pulse frequency modulation

G. Pasetti; L. Fanucci; R. Serventi

2010-03-01T23:59:59.000Z

132

Technology Assessment and Application Guide for the Utility Systems Technologies Voltage Sag Fighter  

Science Conference Proceedings (OSTI)

Voltage sag, a disturbance in a power system defined as a decrease in root mean square (RMS) voltage magnitude lasting from 0.5 to 30 cycles, has been identified as the most prevalent power disturbance experienced by industrial customers. The higher frequency of voltage sages makes them inherently more costly than interruptions since fault-induced, short-duration voltage variations can result in costly loss of production, damaged materials, repair and cleaning of equipment, and lost business opportunitie...

2010-11-29T23:59:59.000Z

133

Energy-efficient datapath scheduling using multiple voltages and dynamic clocking  

Science Conference Proceedings (OSTI)

Recently, dynamic frequency scaling has been explored at the CPU and system levels for power optimization. Low-power datapath scheduling using multiple supply voltages has been well researched. In this work, we develop new datapath scheduling algorithms ... Keywords: High-level synthesis, dynamic frequency clocking, low-power datapath synthesis, multiple voltage scheduling, resource-constrained scheduling, time-constrained scheduling

Saraju P. Mohanty; N. Ranganathan

2005-04-01T23:59:59.000Z

134

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.

Stringfield, R.M.; Wheat, R.M. Jr.

1989-02-21T23:59:59.000Z

135

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

136

HIGH VOLTAGE GENERATOR  

DOE Patents (OSTI)

A generator is presented for producing relatively large currents at high voltages. In general, the invention comprises a plurality of capacitors connected in series by a plurality of switches alternately disposed with the capacitors. The circuit is mounted for movement with respect to contact members and switch closure means so that a load device and power supply are connected across successive numbers of capacitors, while the other capacitors are successively charged with the same power supply.

Schwemin, A.J.

1959-03-17T23:59:59.000Z

137

HIGH VOLTAGE GENERATOR  

DOE Patents (OSTI)

A generator for producing relatively large currents at high voltages is described. In general, the invention comprises a plurality of capacitors connected in series by a plurality of switches alternately disposed with the capacitors. The above-noted circuit is mounted for movement with respect to contact members and switch closure means so that a load device and power supply are connected across successive numbers of capacitors, while the other capacitors are successively charged with the same power supply.

Schwemin, A.J.

1959-03-17T23:59:59.000Z

138

HIGH VOLTAGE ION SOURCE  

DOE Patents (OSTI)

A device is described for providing a source of molecular ions having a large output current and with an accelerated energy of the order of 600 kv. Ions are produced in an ion source which is provided with a water-cooled source grid of metal to effect maximum recombination of atomic ions to molecular ions. A very high accelerating voltage is applied to withdraw and accelerate the molecular ions from the source, and means are provided for dumping the excess electrons at the lowest possible potentials. An accelerating grid is placed adjacent to the source grid and a slotted, grounded accelerating electrode is placed adjacent to the accelerating grid. A potential of about 35 kv is maintained between the source grid and accelerating grid, and a potential of about 600 kv is maintained between the accelerating grid and accelerating electrode. In order to keep at a minimum the large number of oscillating electrons which are created when such high voltages are employed in the vicinity of a strong magnetic field, a plurality of high voltage cascaded shields are employed with a conventional electron dumping system being employed between each shield so as to dump the electrons at the lowest possible potential rather than at 600 kv.

Luce, J.S.

1960-04-19T23:59:59.000Z

139

Automatic voltage-imbalance detector  

DOE Patents (OSTI)

A device is described 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, R.E.; McCormick, J.B.; Kerwin, W.J.

1981-05-20T23:59:59.000Z

140

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

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

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

142

Low-voltage-swing Monolithic DC-DC Conversion  

E-Print Network (OSTI)

Abstract—A low-voltage-swing MOSFET gate drive technique is proposed in this paper for enhancing the efficiency characteristics of high-frequency-switching dc–dc converters. The parasitic power dissipation of a dc–dc converter is reduced by lowering the voltage swing of the power transistor gate drivers. A comprehensive circuit model of the parasitic impedances of a monolithic buck converter is presented. Closed-form expressions for the total power dissipation of a low-swing buck converter are proposed. The effect of reducing the MOSFET gate voltage swings is explored with the proposed circuit model. A range of design parameters is evaluated, permitting the development of a design space for full integration of active and passive devices of a low-swing buck converter on the same die, for a target CMOS technology. The optimum gate voltage swing of a power MOSFET that maximizes efficiency is lower than a standard full voltage swing. An efficiency of 88 % at a switching frequency of 102 MHz is achieved for a voltage conversion from 1.8 to 0.9 V with a low-swing dc–dc converter based on a 0.18- m CMOS technology. The power dissipation of a low-swing dc–dc converter is reduced by 27.9 % as compared to a standard full-swing dc–dc converter. Index Terms—Buck converter, dc–dc converters, enhanced efficiency, high frequency, low power, low swing, monolithic integration, on-chip voltage conversion, parameter optimization, parasitic impedances, power dissipation modeling, power supply, reduced energy dissipation, reduced voltage swing, switching voltage regulator. I.

Volkan Kursun; Siva G. Narendra; Vivek K. De; Eby G. Friedman

2004-01-01T23:59:59.000Z

143

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

144

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

145

FAST: Frequency-aware static timing analysis  

Science Conference Proceedings (OSTI)

Energy is a valuable resource in embedded systems as the lifetime of many such systems is constrained by their battery capacity. Recent advances in processor design have added support for dynamic frequency/voltage scaling (DVS) for saving energy. Recent ... Keywords: Real-time systems, dynamic voltage scaling, scheduling, worst-case execution time analysis

Kiran Seth; Aravindh Anantaraman; Frank Mueller; Eric Rotenberg

2006-02-01T23:59:59.000Z

146

Very-High-Frequency Resonant Boost Converters  

E-Print Network (OSTI)

This paper presents a resonant boost topology suitable for very-high-frequency (VHF, 30-300 MHz) DC-DC power conversion. The proposed design features low device voltage stress, high efficiency over a wide load range, and ...

Perreault, David J.

147

VARIABLE TIME-INTERVAL GENERATOR  

DOE Patents (OSTI)

This patent relates to a pulse generator and more particularly to a time interval generator wherein the time interval between pulses is precisely determined. The variable time generator comprises two oscillators with one having a variable frequency output and the other a fixed frequency output. A frequency divider is connected to the variable oscillator for dividing its frequency by a selected factor and a counter is used for counting the periods of the fixed oscillator occurring during a cycle of the divided frequency of the variable oscillator. This defines the period of the variable oscillator in terms of that of the fixed oscillator. A circuit is provided for selecting as a time interval a predetermined number of periods of the variable oscillator. The output of the generator consists of a first pulse produced by a trigger circuit at the start of the time interval and a second pulse marking the end of the time interval produced by the same trigger circuit.

Gross, J.E.

1959-10-31T23:59:59.000Z

148

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

149

Multi-winding Homopolar Electric Machine Offers Variable ...  

The device can be used as either a motor or a generator. Advantages • Variable voltage and speed design • Internal mechanism allowing for low speed, high

150

High voltage feedthrough bushing  

DOE Patents (OSTI)

A feedthrough bushing for a high voltage diode provides for using compression sealing for all sealing surfaces. A diode assembly includes a central conductor extending through the bushing and a grading ring assembly circumferentially surrounding and coaxial with the central conductor. A flexible conductive plate extends between and compressively seals against the central conductor and the grading ring assembly, wherein the flexibility of the plate allows inner and outer portions of the plate to axially translate for compression sealing against the central conductor and the grading ring assembly, respectively. The inner portion of the plate is bolted to the central conductor for affecting sealing. A compression beam is also bolted to the central conductor and engages the outer portion of the plate to urge the outer portion toward the grading ring assembly to obtain compression sealing therebetween.

Brucker, J.P.

1991-12-31T23:59:59.000Z

151

Voltage Vehicles | Open Energy Information  

Open Energy Info (EERE)

Sector Vehicles Product Voltage Vehicles is a nascent, full-service alternative fuel vehicle distributor specializing in the full spectrum of electric vehicles (EV) and...

152

Humidity, Temperature, and Voltage (Presentation)  

SciTech Connect

An update is given on the work of the PV Quality Assurance Task Force; Group 3: studying the effects of humidity, temperature, and voltage bias.

Wohlgemuth, J.

2012-03-01T23:59:59.000Z

153

Easily disassembled electrical connector for high voltage, high frequency connections  

DOE Patents (OSTI)

An easily accessible electrical connector capable of rapid assembly and disassembly is described wherein a wide metal conductor sheet may be evenly contacted over the entire width of the conductor sheet by opposing surfaces on the connector which provide an even clamping pressure against opposite surfaces of the metal conductor sheet using a single threaded actuating screw. 13 figures.

Milner, J.R.

1994-05-10T23:59:59.000Z

154

Strain-optic voltage monitor  

DOE Patents (OSTI)

A voltage monitor which uses the shift in absorption edge of crystalline material to measure strain resulting from electric field-induced deformation of piezoelectric or electrostrictive material, providing a simple and accurate means for measuring voltage applied either by direct contact with the crystalline material or by subjecting the material to an electric field.

Weiss, J.D.

1995-12-31T23:59:59.000Z

155

Dynamic Voltage Scaling on a Low-Power Microprocessor  

E-Print Network (OSTI)

Power consumption is the limiting factor for the functionality of future wearable devices. Since interactive applications like wireless information access generate bursts of activities, it is important to match the performance of the wearable device accordingly. This paper describes a system with a microprocessor whose speed can be varied (frequency scaling) as well as its input voltage. Voltage scaling is important for reducing power consumption to very low values when operating at low speeds. Measurements show that the energy per instruction at minimal speed (59 MHz) is 1/5 of the energy required at full speed (251 MHz). The frequency and voltage can be scaled dynamically from user space in only 140 ¡ s. This allows power-aware applications to quickly adjust the performance level of the processor whenever the workload changes. 1

Johan Pouwelse; Koen Langendoen; Henk Sips

2001-01-01T23:59:59.000Z

156

Control Techniques to Eliminate Voltage Emergencies in High Performance Processors  

E-Print Network (OSTI)

negligible impact on perfor­ mance and energy. With the ITRS roadmap predicting aggres­ sive drops in supply. At present it is difficult to design a high quality, low impedance power supply system, and industry trends in current variability, often re­ ferred to as the dI/dt problem, can cause supply voltage fluc­ tuations

Martonosi, Margaret

157

Control Techniques to Eliminate Voltage Emergencies in High Performance Processors  

E-Print Network (OSTI)

negligible impact on perfor- mance and energy. With the ITRS roadmap predicting aggres- sive drops in supply. At present it is difficult to design a high quality, low impedance power supply system, and industry trends in current variability, often re- ferred to as the dI/dt problem, can cause supply voltage fluc- tuations

Gupta, Rajiv

158

Two terminal line voltage thermostat  

Science Conference Proceedings (OSTI)

A two terminal line voltage thermostat includes a switch which effectively connects line voltage to a heater load. The entire process is controlled by an integrated circuit microcontroller which is powered by a rectified voltage from a transformer secondary connected to a primary which is in series with the heater load. Backup battery power is provided to maintain limited functions of the microcontroller in the event of overall power loss. The microcontroller is programmed to meet the temperature sensing and control requirements specific to a two terminal electric baseboard heating installation. 7 figs.

Stalsberg, K.J.; Ingalls, J.E.; Hoglund, S.R.

1995-10-10T23:59:59.000Z

159

Current status of CMOS low voltage and low power wireless IC designs  

Science Conference Proceedings (OSTI)

This paper surveys recent research on CMOS low voltage and low power IC designs for wireless applications. Advancements and challenges in using nanometer IC processes are addressed, and the impacts of device scaling on wireless systems are discussed. ... Keywords: CMOS, Integrated Circuits (IC), Low-Power, Low-Voltage, Nanometer, Radio Frequency (RF), Sub-1V, Wireless

Tommy K. Tsang; Mourad N. El-Gamal; Krzysztof Iniewski; Kenneth A. Townsend; James W. Haslett; Yanjie Wang

2007-10-01T23:59:59.000Z

160

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.

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

High-voltage-compatible, fully depleted CCDs  

E-Print Network (OSTI)

result of this high-voltage requirement, we have taken a di?voltage is necessary in order to meet the PSF requirementsrequirements for SNAP have resulted in a need to operate at substrate bias voltages

2006-01-01T23:59:59.000Z

162

Chapter 4 - Understanding Voltage Sags  

Science Conference Proceedings (OSTI)

This chapter of the EPRI Solutions PQ Encyclopedia provides information for understanding the voltage sag, which is the single most potent cause of end user power quality (PQ) problems.

2005-12-31T23:59:59.000Z

163

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.

Kronberg, J.W.

1991-03-05T23:59:59.000Z

164

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

165

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.

Kronberg, James W. (Aiken, SC)

1994-01-01T23:59:59.000Z

166

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

167

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

168

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 the voltage of the output. The preferred embodiment also comprises a low voltage power supply for biasing the FETs at or near an operational voltage. 8 figs.

Christie, D.J.; Dallum, G.E.

1989-12-07T23:59:59.000Z

169

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

170

Performance of Dynamic Voltage Restorer (DVR) against Voltage Sags and Swells Using Space Vector PWM Technique  

Science Conference Proceedings (OSTI)

Due to increasing complexity in the power system, voltage sags are now becoming one of the most significant power quality problems. Voltage sag is a short reduction voltage from nominal voltage, occurs in a short time. Short-lived voltage sags may not ... Keywords: Custom power, power quality, voltage sag, SPWM, SVPWM, DVR, PSCAD/EMTDC.

Palaparthi Ananthababu; Burle Trinadha; K. Ram Charan

2009-12-01T23:59:59.000Z

171

A CMOS threshold voltage reference source for very-low-voltage applications  

Science Conference Proceedings (OSTI)

This paper describes a CMOS voltage reference that makes use of weak inversion CMOS transistors and linear resistors, without the need for bipolar transistors. Its operation is analogous to the bandgap reference voltage, but the reference voltage is ... Keywords: Threshold voltage, Ultra-low-power, Very-low-voltage, Voltage reference

Luis H. C. Ferreira; Tales C. Pimenta; Robson L. Moreno

2008-12-01T23:59:59.000Z

172

Surge voltage suppression in residential power circuits  

Science Conference Proceedings (OSTI)

... Tran- sients in Low Voltage Supply Systems,'' The ... a high-voltage transformer for an oil furnace ... of service entrance SPD of 1960-1970 vintage were ...

2013-05-17T23:59:59.000Z

173

Automated Voltage Control in LHCb  

E-Print Network (OSTI)

LHCb is one of the 4 LHC experiments. In order to ensure the safety of the detector and to maximize efficiency, LHCb needs to coordinate its own operations, in particular the voltage configuration of the different subdetectors, according to the accelerator status. A control software has been developed for this purpose, based on the Finite State Machine toolkit and the SCADA system used for control throughout LHCb (and the other LHC experiments). This software permits to efficiently drive both the Low Voltage (LV) and High Voltage (HV) systems of the 10 different sub-detectors that constitute LHCb, setting each sub-system to the required voltage (easily configurable at run-time) based on the accelerator state. The control software is also responsible for monitoring the state of the Sub-detector voltages and adding it to the event data in the form of status-bits. Safe and yet flexible operation of the LHCb detector has been obtained and automatic actions, triggered by the state changes of the ...

Granado Cardoso, L; Jacobsson, R

2011-01-01T23:59:59.000Z

174

Nonferromagnetic linear variable differential transformer  

DOE Patents (OSTI)

A nonferromagnetic linear variable differential transformer for accurately measuring mechanical displacements in the presence of high magnetic fields is provided. The device utilizes a movable primary coil inside a fixed secondary coil that consists of two series-opposed windings. Operation is such that the secondary output voltage is maintained in phase (depending on polarity) with the primary voltage. The transducer is well-suited to long cable runs and is useful for measuring small displacements in the presence of high or alternating magnetic fields.

Ellis, James F. (Powell, TN); Walstrom, Peter L. (Oak Ridge, TN)

1977-06-14T23:59:59.000Z

175

Portec Voltage Regulators: for Emergency Diesel Generators  

Science Conference Proceedings (OSTI)

This report contains information to help utilities address emergency diesel generator voltage regulator issues.

2004-12-15T23:59:59.000Z

176

Fiber-optic voltage sensor  

DOE Patents (OSTI)

A fiber optic voltage sensor is described which includes a source of light, a reference fiber for receiving a known percentage of the light and an electrostrictive element having terminals across which is applied, a voltage to be measured. The electrostrictive element is responsive to the applied voltage to assume an altered physical state. A measuring fiber also receives a known percentage of light from the light source and is secured about the electrostrictive element. The measuring fiber is provided with a cladding and exhibits an evanescent wave in the cladding. The measuring fiber has a known length which is altered when the electrostrictive element assumes its altered physical state. A differential sensor is provided which senses the intensity of light in both the reference fiber and the measuring fiber and provides an output indicative of the difference between the intensities.

Wood, C.B.

1990-12-31T23:59:59.000Z

177

A 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 picoampers 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, G.M.

1990-12-21T23:59:59.000Z

178

Fiber-optic voltage sensor  

DOE Patents (OSTI)

A fiber optic voltage sensor is described which includes a source of light, a reference fiber for receiving a known percentage of the light and an electrostrictive element having terminals across which is applied, a voltage to be measured. The electrostrictive element is responsive to the applied voltage to assume an altered physical state. A measuring fiber also receives a known percentage of light from the light source and is secured about the electrostrictive element. The measuring fiber is provided with a cladding and exhibits an evanescent wave in the cladding. The measuring fiber has a known length which is altered when the electrostrictive element assumes its altered physical state. A differential sensor is provided which senses the intensity of light in both the reference fiber and the measuring fiber and provides an output indicative of the difference between the intensities.

Wood, C.B.

1990-01-01T23:59:59.000Z

179

Pulsed voltage electrospray ion source and method for preventing analyte electrolysis  

SciTech Connect

An electrospray ion source and method of operation includes the application of pulsed voltage to prevent electrolysis of analytes with a low electrochemical potential. The electrospray ion source can include an emitter, a counter electrode, and a power supply. The emitter can include a liquid conduit, a primary working electrode having a liquid contacting surface, and a spray tip, where the liquid conduit and the working electrode are in liquid communication. The counter electrode can be proximate to, but separated from, the spray tip. The power system can supply voltage to the working electrode in the form of a pulse wave, where the pulse wave oscillates between at least an energized voltage and a relaxation voltage. The relaxation duration of the relaxation voltage can range from 1 millisecond to 35 milliseconds. The pulse duration of the energized voltage can be less than 1 millisecond and the frequency of the pulse wave can range from 30 to 800 Hz.

Kertesz, Vilmos (Knoxville, TN); Van Berkel, Gary (Clinton, TN)

2011-12-27T23:59:59.000Z

180

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

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

Probabilistic voltage assessment and VAR compensation  

SciTech Connect

The system voltage profile subject to system elements' forced outage is accessed. Two system voltage reliability indexes are evaluated: the loss of voltage probability, and the expected voltage violation. A similar set of two voltage reliability indexes are also calculated for every load bus in the system. A simple VAR compensation approach is introduced. It enhances the voltage profile assuming a maximum of three overlapping element outages can occur. For purposes of demonstration, the system and load bus voltage reliability indexes are calculated for the AEP 30-bus system. Results of applying the proposed VAR compensation scheme to the 30-bus system are also presented and discussed.

Sharaf, T.A.M.; Berg, G.J.

1988-01-01T23:59:59.000Z

182

Stability issues in IC Low Drop Out voltage regulators  

E-Print Network (OSTI)

Performance issues of IC Low Drop Out (LDO) voltage regulators, with specific reference to stability, are discussed in this thesis. Evaluation of existing frequency compensation schemes and their performances across operating loads is presented. The problem of instability of the LDO voltage regulator at low Electo Static Resistance (ESR) of the load capacitors and the consequences of this problem are highlighted. As a solution to some of the discussed problems, an alternate LDO voltage regulator topology that is stable with low Electro Static Resistance (ESR) capacitive loads is presented. The proposed scheme, instead of relying on the zero generated by the load capacitor and its ESR combination for stability, generates a zero internally. The LDO voltage regulator is implemented and fabricated in AMI 0.5mm CMOS technology through MOSIS service. It is demonstrated that this scheme realizes robust frequency compensation, facilitates use of Multi Layer Ceramic Capacitors (MLCC) for load of LDO regulators, and improves transient response and noise performance. Test results from the prototype provide an evaluation of the most important parameters of the regulator: ground current, load regulation, line regulation, output noise and start-up time.

Chava, Krishna Chaitanya

2002-01-01T23:59:59.000Z

183

An efficient CMOS rectifier with low-voltage operation for RFID tags  

Science Conference Proceedings (OSTI)

A high-efficiency CMOS rectifier for radio-frequency identification (RFID) applications is presented. Using an on-chip generated clock signal, a new switching scheme is proposed to enhance the power efficiency of the conventional 4 transistor (4T)-cell ... Keywords: frequency 950 MHz, efficient CMOS rectifier, low-voltage operation, RFID tags, radio-frequency identification applications, on-chip generated clock signal, power efficiency, conventional 4 transistor-cell rectifier, charge-transfer transistors, small leakage current, external gate-boosting technique, nominal standard threshold voltage, MOS transistors, CMOS technology, power conversion efficiency

P. Kamalinejad; S. Mirabbasi; V. C. M. Leung

2011-07-01T23:59:59.000Z

184

Radio frequency coaxial feedthrough  

DOE Patents (OSTI)

An improved radio frequency coaxial transmission line vacuum feed-through provided based on the use of a half-wavelength annular dielectric pressure barrier disk, or multiple disks comprising an effective half wavelength structure to eliminate reflections from the barrier surfaces. Gas-tight seals are formed about the outer and inner diameter surfaces of the barrier disk using a sealing technique which generates radial forces sufficient to form seals by forcing the conductor walls against the surfaces of the barrier disks in a manner which does not deform the radii of the inner and outer conductors, thereby preventing enhancement of the electric field at the barrier faces which limits voltage and power handling capabilities of a feedthrough.

Owens, Thomas L. (Kingston, TN)

1989-01-17T23:59:59.000Z

185

High voltage photovoltaic power converter  

DOE Patents (OSTI)

An array of independently connected photovoltaic cells on a semi-insulating substrate contains reflective coatings between the cells to enhance efficiency. A uniform, flat top laser beam profile is illuminated upon the array to produce electrical current having high voltage. An essentially wireless system includes a laser energy source being fed through optic fiber and cast upon the photovoltaic cell array to prevent stray electrical signals prior to use of the current from the array. Direct bandgap, single crystal semiconductor materials, such as GaAs, are commonly used in the array. Useful applications of the system include locations where high voltages are provided to confined spaces such as in explosive detonation, accelerators, photo cathodes and medical appliances.

Haigh, Ronald E. (Arvada, CO); Wojtczuk, Steve (Cambridge, MA); Jacobson, Gerard F. (Livermore, CA); Hagans, Karla G. (Livermore, CA)

2001-01-01T23:59:59.000Z

186

TRANSISTOR HIGH VOLTAGE POWER SUPPLY  

DOE Patents (OSTI)

High voltage, direct current power supplies are described for use with battery powered nuclear detection equipment. The particular advantages of the power supply described, are increased efficiency and reduced size and welght brought about by the use of transistors in the circuit. An important feature resides tn the employment of a pair of transistors in an alternatefiring oscillator circuit having a coupling transformer and other circuit components which are used for interconnecting the various electrodes of the transistors.

Driver, G.E.

1958-07-15T23:59:59.000Z

187

Analysis of the electrical harmonic characteristics of a slip recovery variable speed generating system for wind turbine applications  

SciTech Connect

Variable speed electric generating technology can enhance the general use of wind energy in electric utility applications. This enhancement results from two characteristic properties of variable speed wind turbine generators: an improvement in drive train damping characteristics, which results in reduced structural loading on the entire wind turbine system, and an improvement in the overall efficiency by using a more sophisticated electrical generator. Electronic converter systems are the focus of this investigation -- in particular, the properties of a wound-rotor induction generator with the slip recovery system and direct-current link converter. Experience with solid-state converter systems in large wind turbines is extremely limited. This report presents measurements of electrical performances of the slip recovery system and is limited to the terminal characteristics of the system. Variable speed generating systems working effectively in utility applications will require a satisfactory interface between the turbine/generator pair and the utility network. The electrical testing described herein focuses largely on the interface characteristics of the generating system. A MOD-O wind turbine was connected to a very strong system; thus, the voltage distortion was low and the total harmonic distortion in the utility voltage was less than 3% (within the 5% limit required by most utilities). The largest voltage component of a frequency below 60 Hz was 40 dB down from the 60-Hz< component. 8 refs., 14 figs., 8 tabs.

Herrera, J.I.; Reddoch, T.W.

1988-02-01T23:59:59.000Z

188

Synchronizing carrier frequencies of co-channel amplitude-modulated broadcast  

DOE Patents (OSTI)

Systems and methods are described for carrier-frequency synchronization for improved AM and TV broadcast reception. A method includes synchronizing a carrier frequency of a broadcast signal with a remote reference frequency. An apparatus includes a reference signal receiver; a phase comparator coupled to the reference signal receiver; a voltage controlled oscillator coupled to the phase comparator; and a radio frequency output coupled to the voltage controlled oscillator.

Smith, Stephen F. (London, TN); Moore, James A. (Powell, TN)

2007-05-15T23:59:59.000Z

189

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.

190

Voltage unbalance effects on induction motor performance  

Science Conference Proceedings (OSTI)

The reliability of electric drives and driven motors depends on the quality of the power supply voltage especially in the critical industrial process. In this work, a theoretical study of the effects of voltage unbalances, sags and swells on induction ... Keywords: efficiency, power losses and derating factor, sags, symmetrical components, voltage unbalance

L. Refoufi; H. Bentarzi; F. Z. Dekhandji

2006-09-01T23:59:59.000Z

191

Influence of voltage drop to electric drive with induction motor and voltage sourced inverter  

Science Conference Proceedings (OSTI)

This paper solves problematic of immunity from the voltage drop of the power supply of the electric drive with induction motor with Voltage-Fed inverter. There are reflected opportune control algorithms for the quickly to change of working regime from ... Keywords: electric drive with induction motor, electric drive with voltage sourced inverter, voltage drop

P. Beneš; J. Fo?t; M. Pittermann

2011-09-01T23:59:59.000Z

192

Operational Results of Pulse Shaping Techniques for the High Voltage Convertor Modulator  

Science Conference Proceedings (OSTI)

The High Voltage Converter Modulators (HVCMs) are used to power the RF klystrons used throughout the accelerator systems at Spallation Neutron Source (SNS). The output voltage of the HVCM has significant droop and ripple which, combined with low level RF (LLRF) system limitations, affect performance and efficiency of accelerator cavities. In conjunction with the progress in development of the new HVCM controller, different pulse modulation techniques were implemented and studied on the test modulator. This paper discusses the results of implementation of frequency modulation and phase modulation on output voltage. Operational data, including full average power operation, of test modulator is also discussed. Future plans for the new modulation scheme will be presented.

Patel, Gunjan P [ORNL; Anderson, David E [ORNL; Solley, Dennis J [ORNL; Wezensky, Mark W [ORNL

2012-01-01T23:59:59.000Z

193

Low power, scalable multichannel high voltage controller  

DOE Patents (OSTI)

A low voltage control circuit is provided for individually controlling high voltage power provided over bus lines to a multitude of interconnected loads. An example of a load is a drive for capillary channels in a microfluidic system. Control is distributed from a central high voltage circuit, rather than using a number of large expensive central high voltage circuits to enable reducing circuit size and cost. Voltage is distributed to each individual load and controlled using a number of high voltage controller channel switches connected to high voltage bus lines. The channel switches each include complementary pull up and pull down photo isolator relays with photo isolator switching controlled from the central high voltage circuit to provide a desired bus line voltage. Switching of the photo isolator relays is further controlled in each channel switch using feedback from a resistor divider circuit to maintain the bus voltage swing within desired limits. Current sensing is provided using a switched resistive load in each channel switch, with switching of the resistive loads controlled from the central high voltage circuit.

Stamps, James Frederick (Livermore, CA); Crocker, Robert Ward (Fremont, CA); Yee, Daniel Dadwa (Dublin, CA); Dils, David Wright (Fort Worth, TX)

2006-03-14T23:59:59.000Z

194

Low power, scalable multichannel high voltage controller  

DOE Patents (OSTI)

A low voltage control circuit is provided for individually controlling high voltage power provided over bus lines to a multitude of interconnected loads. An example of a load is a drive for capillary channels in a microfluidic system. Control is distributed from a central high voltage circuit, rather than using a number of large expensive central high voltage circuits to enable reducing circuit size and cost. Voltage is distributed to each individual load and controlled using a number of high voltage controller channel switches connected to high voltage bus lines. The channel switches each include complementary pull up and pull down photo isolator relays with photo isolator switching controlled from the central high voltage circuit to provide a desired bus line voltage. Switching of the photo isolator relays is further controlled in each channel switch using feedback from a resistor divider circuit to maintain the bus voltage swing within desired limits. Current sensing is provided using a switched resistive load in each channel switch, with switching of the resistive loads controlled from the central high voltage circuit.

Stamps, James Frederick (Livermore, CA); Crocker, Robert Ward (Fremont, CA); Yee, Daniel Dadwa (Dublin, CA); Dils, David Wright (Fort Worth, TX)

2008-03-25T23:59:59.000Z

195

Dynamic Voltage Regulation Using Distributed Energy Resources  

Science Conference Proceedings (OSTI)

Many distributed energy resources (DE) are near load centres and equipped with power electronics converters to interface with the grid, therefore it is feasible for DE to provide ancillary services such as voltage regulation, nonactive power compensation, and power factor correction. A synchronous condenser and a microturbine with an inverter interface are implemented in parallel in a distribution system to regulate the local voltage. Voltage control schemes of the inverter and the synchronous condenser are developed. The experimental results show that both the inverter and the synchronous condenser can regulate the local voltage instantaneously, while the dynamic response of the inverter is faster than the synchronous condenser; and that integrated voltage regulation (multiple DE perform voltage regulation) can increase the voltage regulation capability, increase the lifetime of the equipment, and reduce the capital and operation costs.

Xu, Yan [ORNL; Rizy, D Tom [ORNL; Li, Fangxing [ORNL; Kueck, John D [ORNL

2007-01-01T23:59:59.000Z

196

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

197

Variable Screw Compressor, Variable Screw Compressor Suppliers ...  

U.S. Energy Information Administration (EIA)

Variable Screw Compressor Suppliers & air compressor Manufacturers Directory. Source Top Quality Variable Screw Compressor Suppliers, air ...

198

Characterisation of the VELO High Voltage System  

E-Print Network (OSTI)

The high voltage system supplies the bias voltage to the 88 silicon sensors which comprise the LHCb Vertex Locator (VELO). This note describes the results of the tests which have been performed on the hardware of the high voltage system of the VELO. Each individual test detailed in this note corresponds to a specific requirement of the system. These requirements arise primarily from ensuring the safety of the silicon sensors and the quality of the data taken from the VELO modules. The tests performed are in four categories: normal operation of the high voltage system; verification of its stability under operation; discussion of its behaviour in failure modes; and details of operation at low voltage. Noteworthy issues, identified through the tests, include the behaviour of the high voltage modules at voltages below 9V, the current limit that can be applied during ramping of the voltage, and the speed with which the voltage is cut during failures of the system. The results of these tests provide high confidence that the high voltage system can be safely used and demonstrate that low noise is produced by the power supplies. LHCb Public Note, LHCb-2008-009Contents 1

Barinjaka Rakotomiaramanana; Chris Parkes; Lars Eklund

2008-01-01T23:59:59.000Z

199

Strategies for Voltage Control and Transient Stability Assessment  

SciTech Connect

As wind generation grows, its influence on power system performance will becoming increasingly noticeable. Wind generation di#11;ffers from traditional forms of generation in numerous ways though, motivating the need to reconsider the usual approaches to power system assessment and performance enhancement. The project has investigated the impact of wind generation on transient stability and voltage control, identifying and addressing issues at three distinct levels of the power system: 1) at the device level, the physical characteristics of wind turbine generators (WTGs) are quite unlike those of synchronous machines, 2) at the wind-farm level, the provision of reactive support is achieved through coordination of numerous dissimilar devices, rather than straightforward generator control, and 3) from a systems perspective, the location of wind-farms on the sub-transmission network, coupled with the variability inherent in their power output, can cause complex voltage control issues. The project has sought to develop a thorough understanding of the dynamic behaviour of type-3 WTGs, and in particular the WECC generic model. The behaviour of such models is governed by interactions between the continuous dynamics of state variables and discrete events associated with limits. It was shown that these interactions can be quite complex, and may lead to switching deadlock that prevents continuation of the trajectory. Switching hysteresis was proposed for eliminating deadlock situations. Various type-3 WTG models include control blocks that duplicate integrators. It was shown that this leads to non-uniqueness in the conditions governing steady-state, and may result in pre- and post-disturbance equilibria not coinciding. It also gives rise to a zero eigenvalue in the linearized WTG model. In order to eliminate the anomalous behaviour revealed through this investigation, WECC has now released a new generic model for type-3 WTGs. Wind-farms typically incorporate a variety of voltage control equipment including tapchanging transformers, switched capacitors, SVCs, STATCOMs and the WTGs themselves. The project has considered the coordinated control of this equipment, and has addressed a range of issues that arise in wind-farm operation. The #12;first concerns the ability of WTGs to meet reactive power requirements when voltage saturation in the collector network restricts the reactive power availability of individual generators. Secondly, dynamic interactions between voltage regulating devices have been investigated. It was found that under certain realistic conditions, tap-changing transformers may exhibit instability. In order to meet cost, maintenance, fault tolerance and other requirements, it is desirable for voltage control equipment to be treated as an integrated system rather than as independent devices. The resulting high-level scheduling of wind-farm reactive support has been investigated. In addressing this control problem, several forms of future information were considered, including exact future knowledge and stochastic predictions. Deterministic and Stochastic Dynamic Programming techniques were used in the development of control algorithms. The results demonstrated that while exact future knowledge is very useful, simple prediction methods yield little bene#12;fit. The integration of inherently variable wind generation into weak grids, particularly subtransmission networks that are characterized by low X=R ratios, aff#11;ects bus voltages, regulating devices and line flows. The meshed structure of these networks adds to the complexity, especially when wind generation is distributed across multiple nodes. A range of techniques have been considered for analyzing the impact of wind variability on weak grids. Sensitivity analysis, based on the power-flow Jacobian, was used to highlight sections of a system that are most severely a#11;ffected by wind-power variations. A continuation power flow was used to determine parameter changes that reduce the impact of wind-power variability. It was also used to explore interactions betw

Hiskens, Ian A.

2013-09-25T23:59:59.000Z

200

Digital slip frequency generator and method for determining the desired slip frequency  

DOE Patents (OSTI)

The output frequency of an electric power generator is kept constant with variable rotor speed by automatic adjustment of the excitation slip frequency. The invention features a digital slip frequency generator which provides sine and cosine waveforms from a look-up table, which are combined with real and reactive power output of the power generator.

Klein, Frederick F. (Monroeville, PA)

1989-01-01T23:59:59.000Z

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.


201

The effect of DVR location for enhancing voltage sag  

Science Conference Proceedings (OSTI)

Recently, Dynamic Voltage Restorer (DVR) has become a popular power electronic device as a protection for sensitive loads from voltage sag. Voltage sag widely known as one of the major problem in power quality, it is defined as a short reduction of voltage ... Keywords: dynamic voltage restorer, power quality, voltage sag

Rohanim Ibrahim; Ahmed M. A. Haidar; M. Zahim; Herbert Iu

2010-03-01T23:59:59.000Z

202

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

203

Lowering Power using the Voltage Identification Bit  

E-Print Network (OSTI)

Voltage identification is a form of adaptive voltage scaling (AVS). The voltage-identification technique described in this application note enables certain devices in the Virtex®-7 family to be operated at a lower voltage of 0.9V while delivering the same specified performance as that of a device operating at the nominal supply voltage of 1.0V. Voltage identification capable devices consume approximately 30 % lower worst case (maximum) static power and correspondingly dissipate less heat. Reduced power consumption is a desirable characteristic and one that Xilinx 7 series FPGAs fulfill in multiple ways. The primary purpose of the voltage-identification technique is to reduce the worst-case power consumption of-1C devices. However, the significance of the voltage-identification technique goes beyond an individual device dissipating less energy, it also can lower the overall system cost. Power supplies and thermal management requirements are normally specified based on the worst-case power demands of all the system’s components. Although the 7 series FPGAs-1C devices are the most cost-effective, the total cost of a product is the sum of all parts, and costs associated with the power supply and thermal management can be significant. The voltage-identification technique specifically reduces worst-case power consumption, which reduces the overall costs associated with specifying a larger power supply, requiring a heat sink, adding forced air cooling, or including similar devices. This application note shows the technical aspects of implementing the voltage-identification technique and introduces a reference design for the VC707 evaluation kit. It also explains how voltage identification fits into the complete power portfolio of Virtex-7 FPGAs and highlights the benefits of using the voltage-identification technique to reduce power consumption and system costs.

Ken Chapman; Jameel Hussein

2012-01-01T23:59:59.000Z

204

Emergency Diesel Generator Voltage Regulator Guidelines  

Science Conference Proceedings (OSTI)

This product kit, containing six separate documents, provides information to help utilities address emergency diesel generator voltage regulator issues and maintenance.

2005-12-20T23:59:59.000Z

205

Characterisation of the VELO High Voltage System  

E-Print Network (OSTI)

The high voltage system supplies the bias voltage to the 88 silicon sensors which comprise the LHCb Vertex Locator (VELO). This note describes the results of the tests which have been performed on the hardware of the high voltage system of the VELO. Each individual test detailed in this note corresponds to a specific requirement of the system. These requirements arise primarily from ensuring the safety of the silicon sensors and the quality of the data taken from the VELO modules. The tests performed are in four categories: normal operation of the high voltage system; vercation of its stability under operation; discussion of its behaviour in failure modes; and details of operation at low voltage. Noteworthy issues, identified through the tests, include the behaviour of the high voltage modules at voltages below 9V, the current limit that can be applied during ramping of the voltage, and the speed with which the voltage is cut during failures of the system. The results of these tests provide high confidence th...

Rakotomiaramanana, B; Eklund, L

2008-01-01T23:59:59.000Z

206

Characterisation of the VELO High Voltage System  

E-Print Network (OSTI)

The high voltage system supplies the bias voltage to the 88 silicon sensors which comprise the LHCb Vertex Locator (VELO). This note describes the results of the tests which have been performed on the hardware of the high voltage system of the VELO. Each individual test detailed in this note corresponds to a specific requirement of the system. These requirements arise primarily from ensuring the safety of the silicon sensors and the quality of the data taken from the VELO modules. The tests performed are in four categories: normal operation of the high voltage system; verification of its stability under operation; discussion of its behaviour in failure modes; and details of operation at low voltage. Noteworthy issues, identified through the tests, include the behaviour of the high voltage modules at voltages below 9V, the current limit that can be applied during ramping of the voltage, and the speed with which the voltage is cut during failures of the system. The results of these tests provide high confidence...

Rakotomiaramanana, B; Eklund, L

2008-01-01T23:59:59.000Z

207

Enhancing Open Circuit Voltage by Combining Thermoelectric ...  

Science Conference Proceedings (OSTI)

Enhancing Open Circuit Voltage by Combining Thermoelectric Materials and Dye -Sensitized Solar Cell in Series · Estimation of Compressive Strength of High ...

208

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

DOE Green Energy (OSTI)

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

209

Voltage Source Converter Technology for Offshore Grids.  

E-Print Network (OSTI)

??This master thesis has investigated the possible application of voltage source converters (VSC) for the interconnection of offshore installations, i.e. wind farms and petroleum platforms,… (more)

Vormedal, Pål Kristian Myhrer

2010-01-01T23:59:59.000Z

210

Quantum Voltage System Development and Dissemination  

Science Conference Proceedings (OSTI)

... of the unit of electric potential difference, the volt, and precise techniques for measuring voltage are essential to the electrical ... Facilities/Tools Used: ...

2012-11-14T23:59:59.000Z

211

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

SciTech Connect

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

212

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

SciTech Connect

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

213

Capturing power at higher voltages from arrays of microbial fuel cells without voltage reversal  

E-Print Network (OSTI)

is too low to be used directly for many practical applications. For example, a single light emitting diode (LED) requires a minimum voltage of 2 V.2 Thus, effective methods of boosting MFC voltages

214

Aalborg Universitet Mitigation of Voltage Sags in CIGRE Low Voltage Distribution Network  

E-Print Network (OSTI)

software version 15.0. Index Terms--Wind Turbine Generator (WTG), Photovoltaic (PV), Voltage Source of voltage sags. I. INTRODUCTION Power quality, reliability and stability are the prime requirement of modern

Bak-Jensen, Birgitte

215

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

216

Low voltage ride-through capability improvement of wind power generation using dynamic voltage restorer  

Science Conference Proceedings (OSTI)

Recently, the total amount of generation from wind power plants has been increased all over the world. In this situation, a large amount of disconnection of wind generation may give a serious influence in the power system. Consequently, Low Voltage Ride-Through ... Keywords: dynamic voltage restorer, energy storage, fault ride-through, fixed-speed induction generator, low voltage ride-through, voltage sag, wind power generation

Naohiro Hasegawa; Teruhisa Kumano

2010-02-01T23:59:59.000Z

217

Understanding the unbalanced-voltage problem in wind turbine generation  

DOE Green Energy (OSTI)

Most wind turbines are equipped with line-connected induction generators. Induction generators are very attractive as wind turbine generators due to their low cost, ruggedness and the need for little or no maintenance. At constant frequency, the induction generator operates in a small range of speeds and, therefore, it operated with a small range of slips with respect to synchronous speed. Compared to a synchronous generator, an induction generator provides lower stiffness, thus alleviating the mechanical stress. In a weak power system network, an unbalanced load at the distribution lines can cause unbalanced voltage conditions. If an induction generator is connected to an unbalanced voltage, the resulting stator current will be unbalanced. The unbalanced current creates unequal heating (hot spots) on the stator winding. The heat may increase the winding temperature, which degrades the insulation of the winding, i.e., the life expectancy of the winding. Unbalanced currents also create torque pulsation on the shaft resulting in audible noise and extra mechanical stress. This paper explores the unbalanced voltage problem in induction generators. The levels of unbalance and the loads are varied. Experimental and predicted results are presented in this paper.

Muljadi, E.; Butterfield, C.P.; Batan, T.; Yildirim, D.

2000-02-28T23:59:59.000Z

218

Ultra-low voltage resonant tunnelling diode electroabsorption modulator  

E-Print Network (OSTI)

Embedding a double barrier resonant tunnelling diode (RTD) in an unipolar InGaAlAs optical waveguide gives rise to a very low driving voltage electroabsorption modulator (EAM) at optical wavelengths around 1550 nm. The presence of the RTD within the waveguide core introduces high non-linearity and negative differential resistance in the current-voltage (I-V) characteristic of the waveguide. This makes the electric field distribution across the waveguide core strongly dependent on the bias voltage: when the current decreases from the peak to the valley there is an increase of the electric field across the depleted core. The electric field enhancement in the core-depleted layer causes the Franz-Keldysh absorption band-edge to red shift, which is responsible for the electroabsorption effect. High frequency ac signals as low as 100 mV can induce electric field high speed switching, producing substantial light modulation (up to 15 dB) at photon energies slightly lower than the waveguide core band-gap energy. The k...

Figueiredo, J M L; Stanley, C R

2002-01-01T23:59:59.000Z

219

Low-Frequency Signals in Midtropospheric Submonthly Temperature Variance  

Science Conference Proceedings (OSTI)

Low-frequency signals in the daily variability of temperature in the midtroposphere are investigated, thereby complementing published studies of changes in day-to-day temperature variability and in extreme weather events at the surface. The ...

Haig Iskenderian; Richard D. Rosen

2000-07-01T23:59:59.000Z

220

Voltage Stability Studies for Southern Company Services  

Science Conference Proceedings (OSTI)

This report describes a study conducted under an EPRI Tailored Collaboration project to develop and demonstrate procedures for the assessment of voltage security of the Southern Electric System (SES). The contractor used EPRI steady-state analysis tools including VSTAB (Voltage STABility assessment program) to assess stability margins and verified them using EPRI dynamic tools including ETMSP (Extended Transient / Mid-term Stability Program).

1997-12-31T23:59:59.000Z

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.


221

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 when it 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, W.M.

1991-03-19T23:59:59.000Z

222

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

223

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

224

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

225

Flexible method for monitoring fuel cell voltage  

DOE Patents (OSTI)

A method for equalizing the measured voltage of each cluster in a fuel cell stack wherein at least one of the clusters has a different number of cells than the identical number of cells in the remaining clusters by creating a pseudo voltage for the different cell numbered cluster. The average cell voltage of the all of the cells in the fuel cell stack is calculated and multiplied by a constant equal to the difference in the number of cells in the identical cell clusters and the number of cells in the different numbered cell cluster. The resultant product is added to the actual voltage measured across the different numbered cell cluster to create a pseudo voltage which is equivalent in cell number to the number of cells in the other identical numbered cell clusters.

Mowery, Kenneth D. (Noblesville, IN); Ripley, Eugene V. (Russiaville, IN)

2002-01-01T23:59:59.000Z

226

Corona and Motor Voltage Interim Report  

SciTech Connect

It has been suggested that to meet the FreedomCAR objectives for cost, size, weight, efficiency, and reliability higher buss voltages be utilized in HEV and FC automotive applications. The reasoning is that since electric power is equal to the product of voltage and current for a given power a higher voltage and lower current would result in smaller cable and inverter switching components. Consequently, the system can be lighter and smaller. On the other hand, higher voltages are known to require better and thicker electrical insulation that reduce the available slot area for motor windings. One cause of slow insulation breakdown is corona that gradually erodes the insulation and shortens the life expectancy of the motor. This study reports on the results of a study on corona initiating voltages for mush-wound and bobbin-wound stators. A unique testing method is illustrated.

Hsu, J.S.

2005-05-06T23:59:59.000Z

227

Comparative study of gigahertz CMOS LC quadrature voltage-controlled oscillators with relevance to phase noise  

Science Conference Proceedings (OSTI)

This review paper presents a comparative study of published integrated submicron CMOS quadrature voltage-controlled oscillator designs, based on LC resonator tanks operating at gigahertz frequencies. Although special reference to phase noise reduction ... Keywords: LC tanks, Phase noise, Quadrature VCO, RF CMOS circuits

Owen Casha; Ivan Grech; Joseph Micallef

2007-08-01T23:59:59.000Z

228

Incorporating Voltage Fluctuations of the Power Distribution Network into the Transient Analysis of CMOS Logic Gates  

Science Conference Proceedings (OSTI)

Decreased power supply levels have reduced the tolerance to voltage changes within power distribution networks in CMOS integrated circuits. High on-chip currents, required to charge and discharge large on-chip loads while operating at high frequencies, ... Keywords: IR drops, power distribution network, system-on-a-chip

Kevin T. Tang; Eby G. Friedman

2002-05-01T23:59:59.000Z

229

Adaptive fuzzy regulation of the DC-bus capacitor voltage in a wind energy conversion system (WECS)  

Science Conference Proceedings (OSTI)

This paper proposes a new voltage regulator of the DC-bus capacitor of a variable speed wind power generation system based on adaptive fuzzy system. The change in the fuzzy rule base is done using a variable-structure direct adaptive control algorithm ... Keywords: Adaptive control, Fuzzy systems, Wind energy conversion systems

A. L. Elshafei; M. A. Azzouz

2011-05-01T23:59:59.000Z

230

Weather Noise Forcing of Surface Climate Variability  

Science Conference Proceedings (OSTI)

A model-based method to evaluate the role of weather noise forcing of low-frequency variability of surface properties, including SST, surface currents, land surface temperature, and soil moisture, is presented. In this procedure, an “interactive ...

Edwin K. Schneider; Meizhu Fan

2007-09-01T23:59:59.000Z

231

PRESENT AND FUTURE TECHNOLOGY OF HIGH VOLTAGE SYSTEMS FOR NEUTRAL BEAM INJECTORS  

E-Print Network (OSTI)

savings tn the power conditioning transformers would result.power supply would be extremely simple, involving as major components only primary contactors, voltage-variable transformer,transformer reactance. For the LBL 160-kV, 75-A NBSTF Accel power

Baker, W.R.

2011-01-01T23:59:59.000Z

232

Cost of Providing Ancillary Services from Power Plants: Reactive Supply and Voltage Control  

Science Conference Proceedings (OSTI)

This report provides a methodology for determining the variable costs of generating and supplying reactive power to a transmission system, via the generator step-up transformer, for system voltage control. The report examines the costs of additional energy losses, maintenance, repair, and plant aging associated with the generation of reactive power. TR-107270-V3SI contains System of International units.

1997-09-02T23:59:59.000Z

233

Design, Development and Testing of a DSP Based Dynamic Voltage Restorer  

Science Conference Proceedings (OSTI)

The paper describes the design, development and testing of a three phase prototype Voltage Source Inverter (VSI) as part of the Superconducting Magnetic Energy Storage (SMES) system technology development at Variable Energy Cyclotron Centre (VECC), Kolkata. ... Keywords: SMES, DSC, LC filter, Injection Transformer, Space Vector PWM, Software PLL

A. De, S. Kumari, V. K. Khare, S. S. Pal, A. Sadhukhan, V. K. Meshram, S. K. Thakur, S. Saha

2012-12-01T23:59:59.000Z

234

Time and Frequency Portal  

Science Conference Proceedings (OSTI)

NIST Home > Time and Frequency Portal. Time and Frequency Portal. Programs and Projects. CODATA values of the fundamental constants ...

2013-06-27T23:59:59.000Z

235

Performance of a voltage peak detection-based flickermeter  

Science Conference Proceedings (OSTI)

Voltage fluctuations and rapid voltage changes lead to lamps flickering and disturbance of visual perception may occur consequently. For evaluation of the flicker severity level by means of voltage measurement there was developed an instrument called ... Keywords: Matlab Simulink, flickermeter, interharmonics, performance analysis, voltage fluctuation, voltage peak detection

Jiri Drapela

2009-12-01T23:59:59.000Z

236

High-frequency electric field measurement using a toroidal antenna  

DOE Patents (OSTI)

A simple and compact method and apparatus for detecting high frequency electric fields, particularly in the frequency range of 1 MHz to 100 MHz, uses a compact toroidal antenna. For typical geophysical applications the sensor will be used to detect electric fields for a wide range of spectrum starting from about 1 MHz, in particular in the frequency range between 1 to 100 MHz, to detect small objects in the upper few meters of the ground. Time-varying magnetic fields associated with time-varying electric fields induce an emf (voltage) in a toroidal coil. The electric field at the center of (and perpendicular to the plane of) the toroid is shown to be linearly related to this induced voltage. By measuring the voltage across a toroidal coil one can easily and accurately determine the electric field.

Lee, Ki Ha (Lafayette, CA)

2002-01-01T23:59:59.000Z

237

Voltage controlled spintronics device for logic applications.  

SciTech Connect

We consider logic device concepts based on our previously proposed spintronics device element whose magnetization orientation is controlled by application of a bias voltage instead of a magnetic field. The basic building block is the voltage-controlled rotation (VCR) element that consists of a four-layer structure--two ferromagnetic layers separated by both nanometer-thick insulator and metallic spacer layers. The interlayer exchange coupling between the two ferromagnetic layers oscillates as a function of applied voltage. We illustrate transistor-like concepts and re-programmable logic gates based on VCR elements.

Bader, S. D.; You, C.-Y.

1999-09-03T23:59:59.000Z

238

Voltage controlled spintronic devices for logic applications  

SciTech Connect

We consider logic device concepts based on our previously proposed spintronics device element whose magnetization orientation is controlled by application of a bias voltage instead of a magnetic field. The basic building block is the voltage-controlled rotation (VCR) element that consists of a four-layer structure--two ferromagnetic layers separated by both nanometer-thick insulator and metallic spacer layers. The interlayer exchange coupling between the two ferromagnetic layers oscillates as a function of applied voltage. We illustrate transistorlike concepts and reprogrammable logic gates based on VCR elements. (c) 2000 American Institute of Physics.

You, Chun-Yeol [Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Bader, S. D. [Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States)

2000-05-01T23:59:59.000Z

239

Interphase power controller with voltage injection  

Science Conference Proceedings (OSTI)

This paper introduces a new family of Interphase Power Controllers (IPC) based on the principle of voltage injection commonly used in phase-shifting transformers (PST). The voltage injection IPC exhibits power (active and reactive) control characteristics similar to previously defined IPC's and retains their inherent qualities: passive control, short circuit limitation and voltage decoupling. It also provides more flexibility for the adjustment of the operating points. Two promising topologies are described in more detail. One of them offers the potential of retrofitting existing phase-shifting transformers into full-fledged IPC's.

Beauregard, F.; Brochu, J.; Morin, G.; Pelletier, P. (Centre d'Innovation sur le Transport d'Energie du Quebec, Varennes, Quebec (Canada))

1994-10-01T23:59:59.000Z

240

Circuit for monitoring temperature of high-voltage equipment  

DOE Patents (OSTI)

This invention relates to an improved circuit for measuring temperature in a region at high electric potential and generating a read-out of the same in a region at lower potential. The circuit is specially designed to combine high sensitivity, stability, and accuracy. A major portion of the circuit situated in the high-potential region can take the form of an integrated circuit. The preferred form of the circuit includes an input section which is situated in the high-potential region and comprises a temperature-compensated thermocouple circuit for sensing temperature, an oscillator circuit for generating a train of ramp voltages whose rise time varies inversely with the thermocouple output, a comparator and switching circuit for converting the oscillator output to pulses whose frequency is proportional to the thermocouple output, and a light-emitting diode which is energized by these pulses. An optical coupling transmits the light pulses generated by the diode to an output section of the circuit, situated in a region at ground. The output section comprises means for converting the transmitted pulses to electrical pulses of corresponding frequency, means for amplifying the electrical pulses, and means for displaying the frequency of the same. The preferred embodiment of the overall circuit is designed so that the frequency of the output signal in hertz and tenths of hertz is equal to the sensed temperature in degrees and tenths of degrees.

Jacobs, Martin E. (Chillicothe, OH)

1976-01-01T23:59:59.000Z

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.


241

Variable Renewable Generation Can Provide Balancing Control to...  

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

Variable Renewable Generation Can Provide Balancing Control to the Electric Power System e Active Power Control Helps Maintain System Frequency As wind and solar plants become more...

242

Frequency of Precipitation across the Northern U.S. Corn Belt  

Science Conference Proceedings (OSTI)

Knowledge of the frequency of precipitation events can aid in managing water resources, but little is known concerning the regional variability in the frequency of daily precipitation events in the northern U.S. Corn Belt. The frequency ...

B. S. Sharratt; J. Zandlo; G. Spoden

2001-02-01T23:59:59.000Z

243

System for increasing corona inception voltage of insulating oils  

DOE Patents (OSTI)

The Corona Inception Voltage of insulating oils is increased by repetitive cycles of prestressing the oil with a voltage greater than the corona inception voltage, and either simultaneously or serially removing byproducts of corona by evacuation and heating the oil.

Rohwein, Gerald J. (Albuquerque, NM)

1998-01-01T23:59:59.000Z

244

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

245

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

246

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

247

High-voltage-compatible, fully depleted CCDs  

SciTech Connect

We describe charge-coupled device (CCD) developmentactivities at the Lawrence Berkeley National Laboratory (LBNL).Back-illuminated CCDs fabricated on 200-300 mu m thick, fully depleted,high-resistivity silicon substrates are produced in partnership with acommercial CCD foundry.The CCDs are fully depleted by the application ofa substrate bias voltage. Spatial resolution considerations requireoperation of thick, fully depleted CCDs at high substrate bias voltages.We have developed CCDs that are compatible with substrate bias voltagesof at least 200V. This improves spatial resolution for a given thickness,and allows for full depletion of thicker CCDs than previously considered.We have demonstrated full depletion of 650-675 mu m thick CCDs, withpotential applications in direct x-ray detection. In this work we discussthe issues related to high-voltage operation of fully depleted CCDs, aswell as experimental results on high-voltage-compatible CCDs.

Holland, Stephen E.; Bebek, Chris J.; Dawson, Kyle S.; Emes, JohnE.; Fabricius, Max H.; Fairfield, Jessaym A.; Groom, Don E.; Karcher, A.; Kolbe, William F.; Palaio, Nick P.; Roe, Natalie A.; Wang, Guobin

2006-05-15T23:59:59.000Z

248

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 +

249

Assessment of Voltage Security Methods and Tools  

Science Conference Proceedings (OSTI)

To ensure voltage-secure operation of a power system, VAR control devices must be optimally placed and operated. This project assessed tools and methods that claim to help utilities meet these needs and recommended specific enhancements to these tools.

1995-10-26T23:59:59.000Z

250

Superconducting Low Voltage Direct Current (LVDC) Networks  

Science Conference Proceedings (OSTI)

A low voltage dc superconducting distribution network is a challenging future opportunity for power distribution. This report presents a scheme for a superconducting, parallel- connected, multiterminal dc transmission system.

1994-04-27T23:59:59.000Z

251

Spark gap with low breakdown voltage jitter  

SciTech Connect

Novel spark gap devices and electrodes are disclosed. The novel spark gap devices and electrodes are suitable for use in a variety of spark gap device applications. The shape of the electrodes gives rise to local field enhancements and reduces breakdown voltage jitter. Breakdown voltage jitter of approximately 5% has been measured in spark gaps according the invention. Novel electrode geometries and materials are disclosed.

Rohwein, Gerald J. (Albuquerque, NM); Roose, Lars D. (Albuquerque, NM)

1996-01-01T23:59:59.000Z

252

Voltage Control Optimization to Improve Transmission Efficiency  

Science Conference Proceedings (OSTI)

An optimal power flow solution is unique from a conventional power flow solution in that an objective function and user-specified constraints are enforced and satisfied to reach a valid solution. This report presents an analytical study on the optimization of power flow in order to minimize reactive power losses via the modification of generator voltage schedules and transmission switched shunt status. The study examines the potential benefits and applicability of near-real-time voltage control ...

2012-11-08T23:59:59.000Z

253

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)

2007-01-09T23:59:59.000Z

254

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)

2008-07-15T23:59:59.000Z

255

VOLTAGE COLLAPSE AND TRANSIENT ENERGY FUNCTION ANALYSES OF AC/DC SYSTEMS  

E-Print Network (OSTI)

This thesis presents a thorough analysis of saddle-node bifurcations for power system dynamic models, including a third order representation of high voltage direct current (HVDC) transmission, classic ac generator dynamics with reactive flows, and voltage and frequency dependent load models. Extensions of the Point of Collapse and Continuation methods, initially used in ac system voltage stability studies, are applied to the determination of these bifurcation points. These methods are compared and used for calculating bus voltage profiles (“nose ” curves) and collapse points on ac/dc systems of up to 2158 buses, considering a variety of operational limits and controls, namely, ac/dc regulating transformer tap limits, voltage and reactive power limits, and area interchange control. AC generator reactive power limits, HVDC firing angle limits and voltage dependent current order limits (VDCOL) are shown to affect the stability and loadability of these systems. A vector Lyapunov function approach is employed to define a system wide energy function that can be used for stability analysis. This thesis describes the derivation

Claudio A. Cañizares

1991-01-01T23:59:59.000Z

256

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

257

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

258

Cell Voltage Noise Reduction Based on Wavelet in Aluminum ...  

Science Conference Proceedings (OSTI)

Presentation Title, Cell Voltage Noise Reduction Based on Wavelet in Aluminum ... cell voltage signals collected in aluminium electrolysis process are with high ...

259

Dynamic Simulation of Cell Voltage Resonance Effect in Aluminum ...  

Science Conference Proceedings (OSTI)

Dubal Cell Voltage Drop Initiatives towards Low Energy High Amperage Cells · Dynamic Simulation of Cell Voltage Resonance Effect in Aluminum Electrolysis ...

260

Appendix C: California ISO Real Time Voltage Security Assessment...  

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

C: California ISO Real Time Voltage Security Assessment (VSA) Prototype Functional SpecificationsPrototype Development Title Appendix C: California ISO Real Time Voltage Security...

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

Appendix B: California ISO Real Time Voltage Security Assessment...  

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

B: California ISO Real Time Voltage Security Assessment (VSA) Summary Report Title Appendix B: California ISO Real Time Voltage Security Assessment (VSA) Summary Report Publication...

262

Appendix A: California ISO Real Time Voltage Security Assessment...  

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

A: California ISO Real Time Voltage Security Assessment (VSA) Project: Summary of Survey Results on Methodologies for use in Real-Time Voltage Security Assessment Title Appendix A:...

263

Green Island Power Authority Transmission Voltage Support System...  

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

Green Island Power Authority Transmission Voltage Support System Project Green Island Power Authority Transmission Voltage Support System Project Power point presentation...

264

A radio frequency coaxial feedthrough  

DOE Patents (OSTI)

An improved radio frequency coaxial transmission line vacuum feedthrough is provided based on the use of a half-wavelength annular dielectric pressure barrier disk, or multiple disks comprising an effective half wavelength structure to eliminate reflection from the barrier surfaces. Gas-tight seals are formed about the outer and inner diameter surfaces of the barrier disk using a sealing technique which generates radial forces sufficient to form seals by forcing the conductor walls against the surfaces of the barrier disks in a manner which does not deform the radii of the inner and outer conductors, thereby preventing enhancement of the electric field at the barrier faces which limits the voltage and power handling capabilities of a feedthrough.

Owens, T.L.

1987-12-07T23:59:59.000Z

265

A new VME based high voltage power supply for large experiments  

SciTech Connect

A new VME based high voltage power supply has been developed for the D{O} experiment at Fermilab. There are three types of supplies delivering up to {plus_minus}5.6 kV at 1.0 mA or +2.0 kV at 3.0 mA with a set accuracy of 1.5 V and extremely low voltage ripples. Complete computer control has allowed many special features to be developed for the supply, including user-defined control land monitor groups, variable ramp rates, and advanced histogram and graphic functions. 3 refs.

Ahn, S.C.; Angstadt, R.D.; Droege, T.F.; Johnson, M.E.; MacKinnon, B.A.; McNulty, S.E.; Shea, M.F.; Thompson, R.N.; Watson, M.M. [Fermi National Accelerator Lab., Batavia, IL (United States); Franzini, P. [Columbia Univ., New York, NY (United States); Jones, A.A. [Superconducting Super Collider Lab., Dallas, TX (United States); Lopez, M.L. [La Plata Univ. Nacional (Argentina); Wimpenny, S.J.; Yang, M.J. [California Univ., Riverside, CA (United States)

1991-11-01T23:59:59.000Z

266

A new VME based high voltage power supply for large experiments  

Science Conference Proceedings (OSTI)

A new VME based high voltage power supply has been developed for the D{O} experiment at Fermilab. There are three types of supplies delivering up to {plus minus}5.6 kV at 1.0 mA or +2.0 kV at 3.0 mA with a set accuracy of 1.5 V and extremely low voltage ripples. Complete computer control has allowed many special features to be developed for the supply, including user-defined control land monitor groups, variable ramp rates, and advanced histogram and graphic functions. 3 refs.

Ahn, S.C.; Angstadt, R.D.; Droege, T.F.; Johnson, M.E.; MacKinnon, B.A.; McNulty, S.E.; Shea, M.F.; Thompson, R.N.; Watson, M.M. (Fermi National Accelerator Lab., Batavia, IL (United States)); Franzini, P. (Columbia Univ., New York, NY (United States)); Jones, A.A. (Superconducting Super Collider Lab., Dallas, TX (United States)); Lopez, M.L. (La Plata Univ. Nacional (Argentina)); Wimpenny, S.J.; Yang, M.J

1991-11-01T23:59:59.000Z

267

Analog Integrated Circuits and Signal Processing, 42, 231–238, 2005 c ? 2005 Springer Science + Business Media, Inc. Manufactured in The Netherlands. Cascode Monolithic DC-DC Converter for Reliable Operation at High Input Voltages  

E-Print Network (OSTI)

Abstract. A cascode bridge circuit for monolithic switching DC-DC converters operating at high input voltages is proposed in this paper. The proposed circuit can also be used as an I/O buffer to interface circuits operating at significantly different voltages. The circuit technique permits the full integration of the active and passive devices of a switching DC-DC converter with a high voltage conversion ratio in a standard low voltage CMOS technology. The cascode bridge structure guarantees the reliable operation of deep submicrometer MOSFETs without exposure to high voltage stress while operating at high input and output voltages. With the proposed circuit technique, steady-state voltage differences between the terminals of all of the MOSFETs in a switching DC-DC converter are maintained within a range imposed by a target low voltage CMOS technology. High-to-low DC-DC converters operating at input voltages up to three times as high as the maximum voltage that can be directly applied across the terminals of a MOSFET are described. An efficiency of 79.6 % is achieved for 5.4 volts to 0.9 volts conversion assuming a 0.18 µm CMOS technology. The DC-DC converter operates at a switching frequency of 97 MHz while supplying a DC current of 250 mA to the load. Key Words: low voltage DC-DC converters, monolithic voltage regulators, low voltage CMOS technology, MOSFET reliability issues, high voltage stress 1.

Volkan Kursun; Siva G. Narendra; Vivek K. De; Eby G. Friedman

2004-01-01T23:59:59.000Z

268

An accurate continuous calibration system for high voltage current transformer  

SciTech Connect

A continuous calibration system for high voltage current transformers is presented in this paper. The sensor of this system is based on a kind of electronic instrument current transformer, which is a clamp-shape air core coil. This system uses an optical fiber transmission system for its signal transmission and power supply. Finally the digital integrator and fourth-order convolution window algorithm as error calculation methods are realized by the virtual instrument with a personal computer. It is found that this system can calibrate a high voltage current transformer while energized, which means avoiding a long calibrating period in the power system and the loss of power metering expense. At the same time, it has a wide dynamic range and frequency band, and it can achieve a high accuracy measurement in a complex electromagnetic field environment. The experimental results and the on-site operation results presented in the last part of the paper, prove that it can reach the 0.05 accuracy class and is easy to operate on site.

Tong Yue; Li Binhong [College of Electrical and Electronic Engineering, Huazhong University of Science and Technology, Wuhan 430074, Hubei Province (China)

2011-02-15T23:59:59.000Z

269

Method of detecting system function by measuring frequency response  

Science Conference Proceedings (OSTI)

Real-time battery impedance spectrum is acquired using a one-time record. Fast Summation Transformation (FST) is a parallel method of acquiring a real-time battery impedance spectrum using a one-time record that enables battery diagnostics. An excitation current to a battery is a sum of equal amplitude sine waves of frequencies that are octave harmonics spread over a range of interest. A sample frequency is also octave and harmonically related to all frequencies in the sum. The time profile of this signal has a duration that is a few periods of the lowest frequency. The voltage response of the battery, average deleted, is the impedance of the battery in the time domain. Since the excitation frequencies are known and octave and harmonically related, a simple algorithm, FST, processes the time record by rectifying relative to the sine and cosine of each frequency. Another algorithm yields real and imaginary components for each frequency.

Morrison, John L. (Butte, MT); Morrison, William H. (Manchester, CT); Christophersen, Jon P. (Idaho Falls, ID)

2012-04-03T23:59:59.000Z

270

High frequency limit for single-electron pumping operations  

E-Print Network (OSTI)

In this Letter, we study the transient electron transfer phenomena of single-electron devices with alternating external gate voltages. We obtain a high frequency limit for pumping electrons one at a time in single-electron devices. Also, we find that in general the electrical current is not proportional to the frequency of the external signals in the single-electron devices, due to the strong quantum coherence tunneling effect.

Chuan-Yu Lin; Wei-Min Zhang

2010-12-04T23:59:59.000Z

271

An Electronic Voltage Transformer Based on WLAN Technology  

Science Conference Proceedings (OSTI)

An electronic voltage transformer based on WLAN technology is developed for adapting to the development trends of substations’ synthesis automation. The transformer is composed of voltage-to-current conversion unit, signal processing unit and data ... Keywords: electronic voltage transformer, voltage-to-current conversion, WLAN technology, digital interface, wireless communication

Jianqin Feng; Qingming Wang; Fen Niu; Guangzhao Cui; Anping Zheng

2010-03-01T23:59:59.000Z

272

Motor voltage high harmonics influence to efficient energy usage  

Science Conference Proceedings (OSTI)

Analysis of the effect of non-sinusoidal voltages on the three-phase induction motor is presented in the paper. When the induction motors are supplied by a rectangular shape of the voltage inverter with high levels of harmonic voltage (Uh,i ... Keywords: energy efficiency, harmonics, induction motor, non-sinusoidal voltage, power losses

Miloje M. Kostic; Branka B. Kostic

2011-07-01T23:59:59.000Z

273

Distribution System Voltage Performance Analysis for High-Penetration Photovoltaics  

DOE Green Energy (OSTI)

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

274

Optimal Compensation Algorithms for a Dynamic Voltage Restorer  

Science Conference Proceedings (OSTI)

The Dynamic Voltage Restorer (DVR) as an electronics based custom device, is used to protect sensitive loads from the voltage sags in the power distribution system. With the rapid technology advancement in industrial control processes, it is experiencing ... Keywords: Dynamic Voltage Restorer (DVR), power quality, voltage sag, Zero Active Power Compensation (ZAPC), Minimal Active Power Compensation (MAPC)

Deng Pan; Chen Zhongming; Jiang Peng; Abdelkrim Benchaib; Guillaume De Preville

2010-06-01T23:59:59.000Z

275

Analysis of Voltage Rise Effect on Distribution Network with Distributed  

E-Print Network (OSTI)

appearance of hidden loads and affect the voltage profile of low voltage distribution network. To overcomeAnalysis of Voltage Rise Effect on Distribution Network with Distributed Generation M. A. Mahmud. This paper presents a detail analysis of how does voltage rise on distribution network due to the penetration

Pota, Himanshu Roy

276

Cascode buffer for monolithic voltage conversion operating at high input supply voltages  

E-Print Network (OSTI)

A high-to-low switching DC-DC converter that operates at input supply voltages up to two times as high as the maximum voltage permitted in a nanometer CMOS technology is proposed in this paper. The circuit technique is based on a cascode bridge that maintains the steady-state voltage differences among the terminals of all of the transistors within a range imposed by a specific fabrication technology. The proposed circuit technique permits the full integration of active and passive devices of a switching DC-DC converter with a high voltage conversion ratio in a standard low voltage CMOS process. An efficiency of 87.8 % is achieved for 3.6 volts to 0.9 volts conversion assuming

Volkan Kursun; Gerhard Schrom; Vivek K. De; Eby G. Friedman; Siva G. Narendra

2005-01-01T23:59:59.000Z

277

Energy Savings of Variable Speed Motors  

E-Print Network (OSTI)

This paper investigates the energy savings available by utilizing variable speed motors on pump and fan applications. Conventional control of flow or pressure in process plants is normally accomplished by throttling the various streams with control valves. Depending on the system and the actual operating conditions, this throttling may consume a considerable amount of energy. The hydraulics of different systems are investigated to generalize high energy saving applications. Typical pump characteristics at varying speeds are investigated since most performance curves are only available at a constant speed. The various types of variable speed electric motors are discussed. However, the primary variable speed system recommended is a variable frequency speed system which utilizes standard induction motors. Specific cases of centrifugal pump applications and cooling tower fan service are presented. Turndown frequencies, stream factors, and electric rates are included in the evaluation. The energy savings of a variable speed system becomes significant when flow rates vary widely and the electrical rates are high.

Fishel, F. D.

1979-01-01T23:59:59.000Z

278

Electronic circuit for measuring series connected electrochemical cell voltages  

DOE Patents (OSTI)

An electronic circuit for measuring voltage signals in an energy storage device is disclosed. The electronic circuit includes a plurality of energy storage cells forming the energy storage device. A voltage divider circuit is connected to at least one of the energy storage cells. A current regulating circuit is provided for regulating the current through the voltage divider circuit. A voltage measurement node is associated with the voltage divider circuit for producing a voltage signal which is proportional to the voltage across the energy storage cell.

Ashtiani, Cyrus N. (West Bloomfield, MI); Stuart, Thomas A. (Toledo, OH)

2000-01-01T23:59:59.000Z

279

Developments in line-voltage thermostats  

Science Conference Proceedings (OSTI)

A thermostat that provides reliable, accurate temperature control is the key to a comfortable, efficient space-heating system. The lack of a commercially available line-voltage thermostat that is affordable and performs well has been a significant factor in limiting the comfort and popularity of zoned residential electric heating systems. With EPRI support, two manufacturers have developed innovative, electronics-based line-voltage thermostats that offer a cost-effective control option for creating a comfortable environment with zoned electric heat. These thermostats also may help reduce energy consumption.

Kesselring, J.

1992-09-01T23:59:59.000Z

280

Removing Spurious Low-Frequency Variability in Drifter Velocities  

Science Conference Proceedings (OSTI)

Satellite-tracked drifting buoys of the Global Drifter Program have drogues, centered at 15-m depth, to minimize direct wind forcing and Stokes drift. Drogue presence has historically been determined from submergence or tether strain records. ...

Rick Lumpkin; Semyon A. Grodsky; Luca Centurioni; Marie-Helene Rio; James A. Carton; Dongkyu Lee

2013-02-01T23:59:59.000Z

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.


281

Singular Modes and Low-Frequency Atmospheric Variability  

Science Conference Proceedings (OSTI)

Recently, it has been shown that the EOFs (empirical orthogonal functions) of the solutions of a stationary linear model to an ensemble of white noise forcing fields are the Schmidt modes (singular modes) of the model' linear operator. If the ...

Werner Metz

1994-06-01T23:59:59.000Z

282

Low-Frequency Pycnocline Variability in the Northeast Pacific  

Science Conference Proceedings (OSTI)

The output from an ocean general circulation model (OGCM) driven by observed surface forcing is used in conjunction with simpler dynamical models to examine the physical mechanisms responsible for interannual to interdecadal pycnocline ...

Antonietta Capotondi; Michael A. Alexander; Clara Deser; Arthur J. Miller

2005-08-01T23:59:59.000Z

283

A fuzzy logic controller to increase fault ride-through capability of variable speed wind turbines  

Science Conference Proceedings (OSTI)

A fuzzy controller for improving Fault Ride-Through (FRT) capability of Variable Speed Wind Turbines (WTs) equipped with Doubly Fed Induction Generator (DFIG) is presented. The controller is designed in order to compensate the voltage at the Point of ...

Geev Mokryani, Pierluigi Siano, Antonio Piccolo, Vito Calderaro

2012-01-01T23:59:59.000Z

284

Group 3: Humidity, Temperature and Voltage (Presentation)  

SciTech Connect

This is a summary of the work of Group 3 of the International PV QA Task Force. 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.

2013-09-01T23:59:59.000Z

285

High voltage VLF testing of power cables  

SciTech Connect

This publication describes a laboratory test program conducted with the objective to develop a test that would replace the existing dc withstand test. The article describes the methodology used to establish the voltage duration and magnitude of VLF (0.1 Hz) high voltage field tests suitable for crosslinked polyethylene (XLPE) insulated power cable. The results show that the voltage breakdown of laboratory aged XLPE cable at 0.1 Hz is approximately equal to that at 60 Hz, that proof tests at 0.1 Hz is approximately equal to that at 60 Hz, that proof tests at 0.1 Hz cause very little damage to the cable, and that 0.1 Hz testing appears to be a satisfactory alternate to dc testing. Preliminary values are suggested for voltage magnitude and time duration of cable acceptance, maintenance and proof tests at 0.1 Hz for XLPE cable rated up to 35 kV. A program is underway to similarly evaluate samples of service-aged XLPE cable; as well as to demonstrate the use of the preliminary test values at typical utility installations.

Eager, G.S.; Katz, C.; Fryszczyn, B. [Cable Technology Labs., Inc., New Brunswick, NJ (United States); Densley, J. [Ontario Hydro, Toronto, Ontario (Canada); Bernstein, B.S. [EPRI, Washington, DC (United States)

1997-04-01T23:59:59.000Z

286

Application of Newton's optimal power flow in voltage/reactive power control  

Science Conference Proceedings (OSTI)

This paper considers an application of Newton's optimal power flow to the solution of the secondary voltage/reactive power control in transmission networks. An efficient computer program based on the latest achievements in the sparse matrix/vector techniques has been developed for this purpose. It is characterized by good robustness, accuracy and speed. A combined objective function appropriate for various system load levels with suitable constraints, for treatment of the power system security and economy is also proposed. For the real-time voltage/reactive power control, a suboptimal power flow procedure has been derived by using the reduced set of control variables. This procedure is based on the sensitivity theory applied to the determination of zones for the secondary voltage/reactive power control and corresponding reduced set of regulating sources, whose reactive outputs represent control variables in the optimal power flow program. As a result, the optimal power flow program output becomes a schedule to be used by operators in the process of the real-time voltage/reactive power control in both normal and emergency operating states.

Bjelogrlic, M.; Babic, B.S. (Electric Power Board of Serbia, Belgrade (YU)); Calovic, M.S. (Dept. of Electrical Engineering, University of Belgrade, Belgrade (YU)); Ristanovic, P. (Institute Nikola Tesla, Belgrade (YU))

1990-11-01T23:59:59.000Z

287

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

288

The Constant Voltage Transformer (CVT) for Mitigating Effects of Voltage Sags on Industrial Equipment  

E-Print Network (OSTI)

Electric quality problems associated with power interactions between distribution and industrial process control systems can be prevented. Surveys of large users that buy power at the transmission and distribution voltages turn up relatively few complaints about the quality of their incoming power, while surveys of small users connected at secondary voltages tum up numerous complaints about the quality of their incoming power. Three major changes in the characteristics of customer loads and power distribution systems have altered the nature of the power quality equation: (I) greater sensitivity of devices and equipment to electric power variations, (2) the interconnection of sensitive loads in extensive networks and automated processes, and (3) an increase in loads that use power electronics in some type of power conversion configuration [1][2]. This paper presents applications of the constant-voltage transformer (CVT) for mitigating the effects of electric service voltage sags on industrial equipment in an oil refinery. Unlike conventional transformers, the CVT or ferro-resonant transformer allows the core to become saturated with magnetic flux, which maintains a relatively constant output voltage during input voltage variations such as undervoltages, overvoltages, and harmonic distortion.

Ferraro, R. J.; Osborne, R.; Stephens, R.

2000-04-01T23:59:59.000Z

289

Recommended Rest Frequencies  

Science Conference Proceedings (OSTI)

Return to Table of Contents NIST Recommended Rest Frequencies for Observed Interstellar Molecular Microwave Transitions. by Frank J. Lovas. ...

290

Spin as state variable for computation: prospects and perspectives  

Science Conference Proceedings (OSTI)

Recent experiments on spin devices like magnetic tunnel junctions (MTJ's), domain wall magnets (DWM) and spin valves have led to the possibility of having very high density on-chip memories and logic. While the possibility of having on-chip spin transfer ... Keywords: low power, spin device, state variable, ultra low voltage

Kaushik Roy

2012-07-01T23:59:59.000Z

291

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

292

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

293

LOW VOLTAGE 14 Mev NEUTRON SOURCE  

DOE Patents (OSTI)

An apparatus yielding high-energy neutrons at the rate of 10/sup 8/ or more per second by the D,T or D,D reactions is described. The deuterium gas filling is ionized by electrons emitted from a filament, and the resulting ions are focused into a beam and accelerated against a fixed target. The apparatus is built in accordance with the relationship V/sub s/ = A--B log pd, where V/sub s/ is the sparking voltage, p the gas pressure, and d the gap length between the high voltage electrodes. Typical parameters to obtain the high neutron yields are 55 to 80 kv, 0.5 to 7.0 ma beam current, 5 to 12 microns D/sub 2/, and a gap length of 1 centimeter.

Little, R.N. Jr.; Graves, E.R.

1959-09-29T23:59:59.000Z

294

Low Swing Dual Threshold Voltage Domino Logic  

E-Print Network (OSTI)

A low swing domino logic technique is proposed to decrease power consumption without sacrificing noise immunity. With the proposed low swing domino logic circuit technique, active power consumption is reduced by up to 9.4% while improving the noise immunity by 2.6% as compared to standard domino logic circuits. It is also shown that by applying a low swing contention reduction technique, the power savings can be further increased by 6.7% while the delay can be improved by 8.6%. A simple and efficient dual threshold voltage (dual-V t ) circuit technique that incorporates low swing signals is also proposed. It is shown that the proposed dual-V technique reduces the standby leakage current by approximately 235 times while offering enhanced delay characteristics as compared to a standard low threshold voltage implementation.

Volkan Kursun; Eby G. Friedman

2002-01-01T23:59:59.000Z

295

Eastern Frequency Response Study  

Science Conference Proceedings (OSTI)

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

296

HIGH VOLTAGE, HIGH CURRENT SPARK GAP SWITCH  

DOE Patents (OSTI)

A high voltage and current spark gap switch comprising two main electrodes insulatingly supported in opposed spaced relationship and a middle electrode supported medially between the main electrodes and symmetrically about the median line of the main electrodes is described. The middle electrode has a perforation aligned with the median line and an irradiation electrode insulatingly supported in the body of the middle electrode normal to the median line and protruding into the perforation. (AEC)

Dike, R.S.; Lier, D.W.; Schofield, A.E.; Tuck, J.L.

1962-04-17T23:59:59.000Z

297

Low-Voltage Cable Aging Management Guidance  

Science Conference Proceedings (OSTI)

This report, intended for use by power plant engineers and craft and administrative personnel who are responsible for cable system aging management, provides guidance on the effective and efficient application of current information and techniques related to aging and condition monitoring (CM) of low-voltage cables. The identification of cables that are prone to early aging and the timely replacement or repair of cables that are degraded will minimize unnecessary power losses, unplanned shutdowns, ...

2013-12-23T23:59:59.000Z

298

A compact high voltage pulse generator  

SciTech Connect

A compact, easily transportable, pulse generator has been developed for a variety of applications that require a pulse duration in the range of 1 {mu} sec., voltages from 150 to 300 KV and current levels from 2,000 to 3,000 amps. The generator has a simple cylindrical configuration and modular construction to facilitate assembly and service. The generator may be operated single-pulse or repetitively at pulse repetition rates to 50 Hz in a burst mode.

Rohwein, G.J.; Babcock, S.R.

1994-07-01T23:59:59.000Z

299

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

300

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. 6 figs.

Crawford, T.M.; Davidson, J.R.; Woods, G.K.

1999-08-17T23:59:59.000Z

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

Physical design with multiple on-chip voltages  

Science Conference Proceedings (OSTI)

Supply voltage is one of the dominant factors that determine the timing performance and power consumption of VLSI chips. For digital systems with a single supply voltage, some logic devices typically operate faster or more frequently than necessary, ...

Chunhong Chen

2002-04-01T23:59:59.000Z

302

NIST Online Museum of Quantum Voltage Standards, 1990s  

Science Conference Proceedings (OSTI)

... (Artifact 7, Citation: SP Benz, "Superconductor-normal-superconductor junctions for programmable voltage standards," Appl. Phys. Lett., vol. 67, pp. ...

2013-02-28T23:59:59.000Z

303

Activated Sintering, Spark Plasma Sintering and High Voltage ...  

Science Conference Proceedings (OSTI)

Mar 4, 2013 ... Novel Synthesis and Consolidation of Powder Materials : Activated Sintering, Spark Plasma Sintering and High Voltage Electric Discharge ...

304

Dubal Cell Voltage Drop Initiatives towards Low Energy High ...  

Science Conference Proceedings (OSTI)

About this Abstract. Meeting, 2014 TMS Annual Meeting & Exhibition. Symposium , Aluminum Reduction Technology. Presentation Title, DUBAL CELL VOLTAGE ...

305

Temperature Fitting Method Predicting Equidistant Voltage Drop of ...  

Science Conference Proceedings (OSTI)

High Temperature Compression Test to Determine the Anode Paste ... Temperature Fitting Method Predicting Equidistant Voltage Drop of Anode Nod in  ...

306

Development of the Platform-Mounted Dynamic Voltage Restorer (PMDVR)  

Science Conference Proceedings (OSTI)

The uninterrupted supply of electrical power is critical for many commercial utility customers with sensitive loads. A voltage sag of a few cycles could cause loss of many thousands of dollars due to lost production from process stoppage and associated clean-up issues. The Platform Mounted Dynamic Voltage Restorer (PMDVR) is a distribution voltage level device that compensates for changes in supply line voltage to maintain acceptable input power to customers.

1998-12-31T23:59:59.000Z

307

ACCELERATED AGING STUDY OF MACHINE WINDING INSULATION UNDER AC AND HIGH FREQUENCY PULSE VOLTAGE APPLICATION.  

E-Print Network (OSTI)

?? It is common practice to perform accelerated aging with 60 Hz ac to determine the lifetime characteristics of insulation used in the machine. Comparable… (more)

Chalise, Sajal Raj

2010-01-01T23:59:59.000Z

308

System for increasing corona inception voltage of insulating oils  

DOE Patents (OSTI)

The Corona Inception Voltage of insulating oils is increased by repetitive cycles of prestressing the oil with a voltage greater than the corona inception voltage, and either simultaneously or serially removing byproducts of corona by evacuation and heating the oil. 5 figs.

Rohwein, G.J.

1998-05-19T23:59:59.000Z

309

Research of Dynamic Voltage Restorer Based on Repetitive Control Strategy  

Science Conference Proceedings (OSTI)

This paper introduces a dynamic voltage restorer with independent three-phase structure, which is controlled on repetitive control strategy. Computer simulation of the whole repetitive control system is performed by Matlab/Simulink, and the results show ... Keywords: Dynamic Voltage Restorer, Repetitive Control, Voltage Sag

Tianyu Liu

2012-10-01T23:59:59.000Z

310

Distributed Generation Source Stiffness and Its Impact on Voltage Distortion  

Science Conference Proceedings (OSTI)

Distributed generators with loads that create high harmonics can cause excessive voltage distortion. This report's objective was to evaluate under controlled laboratory conditions voltage distortion resulting from application of nonlinear load for three different types of rotary generators and one inverter-based generator. Test results also were used to verify the analytical model for predicting voltage distortion from nonlinear load application.

2001-11-27T23:59:59.000Z

311

Selective compensation of voltage harmonics in grid-connected microgrids  

E-Print Network (OSTI)

1 Selective compensation of voltage harmonics in grid-connected microgrids Mehdi Savaghebia , Juan is proposed for selective compensation of main voltage harmonics in a grid- connected microgrid. The aim level. Keywords Distributed Generator (DG); microgrid; grid-connected; voltage harmonics compensation. 1

Vasquez, Juan Carlos

312

Secondary Control for Voltage Unbalance Compensation in an Islanded Microgrid  

E-Print Network (OSTI)

Secondary Control for Voltage Unbalance Compensation in an Islanded Microgrid Mehdi Savaghebi1 microgrid. The aim of the proposed control approach is to enhance the voltage quality at the point of common unbalance. Keywords-distributed generation; microgrid; secondary control; voltage unbalance compensation I

Vasquez, Juan Carlos

313

A Numerical Model for Low-Frequency Equatorial Dynamics  

Science Conference Proceedings (OSTI)

A fast, efficient numerical procedure for modeling the linear low-frequency motions on an equatorial beta plane is developed. The model is capable of simulating the seasonal and interannual variability in realistically shaped ocean basins forced ...

Mark A. Cane; Randall J. Patton

1984-12-01T23:59:59.000Z

314

Multiscale Low-Frequency Circulation Modes in the Global Atmosphere  

Science Conference Proceedings (OSTI)

In this paper, fundamental multiscale circulation modes in the global atmosphere are identified with the objective of providing better understanding of atmospheric low-frequency variabilities over a wide range of spatial and temporal scales. With ...

K-M. Lau; P-J. Sheu; I-S. Kang

1994-05-01T23:59:59.000Z

315

Quantum teleportation of optical images with frequency conversion  

E-Print Network (OSTI)

We describe a new version of continuous variables quantum holographic teleportation of optical images. Unlike the previously proposed scheme, it is based on the continuous variables quantum entanglement between the light fields of different frequencies and allows for the wavelength conversion between the original and the teleported images. The frequency tunable holographic teleportation protocol can be used as a part of light-matter interface in parallel quantum information processing and parallel quantum memory

Liubov V. Magdenko; Ivan V. Sokolov; Mikhail I. Kolobov

2006-02-24T23:59:59.000Z

316

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

317

A new current source GTO inverter with sinusoidal output voltage and current  

SciTech Connect

A new current source inverter with sinusoidal output voltage and current is presented. Gate turn-off thyristors (GTO's) and pulsewidth modulation (PWM) control techniques are used in the current source inverter to produce the sinusoidal output voltage and current. Three capacitors are connected to the ac output terminals to absorb overvoltages which occur when the GTO current is cut off and to provide a filter function for reducing harmonics in the output current. Voltage spikes, which have been a serious problem in the practical application of this inverter, are suppressed by adding gate pulses which force the inverter into a state of shoot-through. Moreover, this inverter permits the capacitance of an ac output terminal capacitor for absorbing overvoltages to be reduced to one-tenth or less of that of a commutating capacitor in a conventional thyristor type current source inverter. A 3.7-kW induction motor is driven by the inverter. The motor efficiency and noise level are measured and compared with those obtained when the motor is driven by a conventional voltage source PWM inverter. An operating efficiency five or six percent higher and noise level 10 dB lower are obtained for the former. Therefore, this current source GTO inverter is very suitable for ac motor variable speed drives.

Hombu, M.; Matsuda, Y.; Ueda, A.; Ueda, S.

1985-09-01T23:59:59.000Z

318

primary frequency standards  

Science Conference Proceedings (OSTI)

NIST-F1 Cesium Fountain Atomic Clock The Primary Time and Frequency Standard for the United States. NIST-F1, the nation's ...

2013-02-04T23:59:59.000Z

319

Low voltage operation of plasma focus  

SciTech Connect

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 {mu}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 focus inductance. 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.

Shukla, Rohit; Sharma, S. K.; Banerjee, P.; Das, R.; Deb, P.; Prabahar, T.; Das, B. K.; Adhikary, B.; Shyam, A. [Energetics and Electromagnetics Division, Facility for Electromagnetic Systems, Bhabha Atomic Research Center, Visakhapatanam, A.P. 530012 (India)

2010-08-15T23:59:59.000Z

320

High Voltage GaN Schottky Rectifiers  

SciTech Connect

Mesa and planar GaN Schottky diode rectifiers with reverse breakdown voltages (V{sub RB}) up to 550V and >2000V, respectively, have been fabricated. The on-state resistance, R{sub ON}, was 6m{Omega}{center_dot} cm{sup 2} and 0.8{Omega}cm{sup 2}, respectively, producing figure-of-merit values for (V{sub RB}){sup 2}/R{sub ON} in the range 5-48 MW{center_dot}cm{sup -2}. At low biases the reverse leakage current was proportional to the size of the rectifying contact perimeter, while at high biases the current was proportional to the area of this contact. These results suggest that at low reverse biases, the leakage is dominated by the surface component, while at higher biases the bulk component dominates. On-state voltages were 3.5V for the 550V diodes and {ge}15 for the 2kV diodes. Reverse recovery times were <0.2{micro}sec for devices switched from a forward current density of {approx}500A{center_dot}cm{sup -2} to a reverse bias of 100V.

CAO,X.A.; CHO,H.; CHU,S.N.G.; CHUO,C.-C.; CHYI,J.-I.; DANG,G.T.; HAN,JUNG; LEE,C.-M.; PEARTON,S.J.; REN,F.; WILSON,R.G.; ZHANG,A.P.

1999-10-25T23:59:59.000Z

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.


321

Understanding Inertial and Frequency Response of Wind Power Plants: Preprint  

DOE Green Energy (OSTI)

The objective of this paper is to analyze and quantify the inertia and frequency responses of wind power plants with different wind turbine technologies (particularly those of fixed speed, variable slip with rotor-resistance controls, and variable speed with vector controls).

Muljadi, E.; Gevorgian, V.; Singh, M.; Santoso, S.

2012-07-01T23:59:59.000Z

322

Intraseasonal Variability in a Barotropic Model with Seasonal Forcing  

Science Conference Proceedings (OSTI)

It has recently been suggested that oscillatory topographic instability could contribute to low-frequency variability over the Northern Hemisphere midlatitudes. A barotropic potential vorticity model, with a hierarchy of forcing and topography ...

Christopher M. Strong; Fei-Fei Jin; Michael Ghil

1993-09-01T23:59:59.000Z

323

Climatology and Interannual Variability of North Atlantic Hurricane Tracks  

Science Conference Proceedings (OSTI)

The spatial and temporal variability of North Atlantic hurricane tracks and its possible association with the annual hurricane landfall frequency along the U.S. East Coast are studied using principal component analysis (PCA) of hurricane track ...

Lian Xie; Tingzhuang Yan; Leonard J. Pietrafesa; John M. Morrison; Thomas Karl

2005-12-01T23:59:59.000Z

324

Dynamics of Charged-particle Between the DC Voltage Biased Plane-Parallel Conductors  

E-Print Network (OSTI)

The analytic description to an oscillating charged-particle between the DC voltage biased plane-parallel conductors is presented. Contrary to the traditional belief in which the oscillatory behavior of the charged-particle in a uniform DC field is attributed to the reversal in the sign of the particle's charge polarity as it rebounds between the two electrodes, the analytic description of the phenomenon presented in this work reveals that such requirement is not necessary for the charged-particle oscillation. Since the system involves a spatially oscillating charged-particle, it represents a natural prototype for illuminating electric dipole radiation. By varying the DC bias voltage across the plane-parallel electrodes, the frequency of radiated electromagnetic waves can be adjusted. The device based on charged-particle oscillation is predicted to generate the coherent electromagnetic waves in the microwave to the X-ray regions of the spectrum, which includes the technologically important terahertz, the infra...

Cho, Sung Nae

2011-01-01T23:59:59.000Z

325

Transient power supply voltage (v{sub DDT}) analysis for detecting IC defects  

SciTech Connect

Transient power supply voltage (V{sub DDT}) analysis is a new testing technique demonstrated as a powerful alternative and complement to I{sub DDQ} testing. V{sub DDT} takes advantage of the limited response time of a voltage supply to the changing power demands of an IC during operation. Changes in the V{sub DD} response time are used to detect increases in power demand with resolutions of 100 nA at 100 kHz, 1 {mu}A at 1 MHz, and 2.5 {mu}A at 1.5 MHz. These current sensitivities have been shown for ICs with quiescent currents < 0.1 {mu}A and > 300 {mu}A. The V{sub DDT} signal acquisition protocols, frequency versus sensitivity tradeoffs, hardware considerations and limitations, data examples, and areas for future research are described.

Cole, E.I. Jr.; Soden, J.M.; Beegle, R.W. [and others

1997-04-01T23:59:59.000Z

326

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

327

Estimating frequency of change  

Science Conference Proceedings (OSTI)

Many online data sources are updated autonomously and independently. In this article, we make the case for estimating the change frequency of data to improve Web crawlers, Web caches and to help data mining. We first identify various scenarios, where ... Keywords: Change frequency estimation, Poisson process

Junghoo Cho; Hector Garcia-Molina

2003-08-01T23:59:59.000Z

328

A New Parsimonious Methodology of Mapping the Spatial Variability of Annual Maximum Rainfall in Mountainous Environments  

Science Conference Proceedings (OSTI)

The estimation of rare frequency rainfall is an essential prerequisite for the design of engineering structures and to determine risk areas. Index-based methods are among the most applied for regional frequency analysis of hydrological variables ...

G. Boni; A. Parodi; F. Siccardi

2008-06-01T23:59:59.000Z

329

Microfabricated ion frequency standard  

DOE Patents (OSTI)

A microfabricated ion frequency standard (i.e. an ion clock) is disclosed with a permanently-sealed vacuum package containing a source of ytterbium (Yb) ions and an octupole ion trap. The source of Yb ions is a micro-hotplate which generates Yb atoms which are then ionized by a ultraviolet light-emitting diode or a field-emission electron source. The octupole ion trap, which confines the Yb ions, is formed from suspended electrodes on a number of stacked-up substrates. A microwave source excites a ground-state transition frequency of the Yb ions, with a frequency-doubled vertical-external-cavity laser (VECSEL) then exciting the Yb ions up to an excited state to produce fluorescent light which is used to tune the microwave source to the ground-state transition frequency, with the microwave source providing a precise frequency output for the ion clock.

Schwindt, Peter (Albuquerque, NM); Biedermann, Grant (Albuquerque, NM); Blain, Matthew G. (Albuquerque, NM); Stick, Daniel L. (Albuquerque, NM); Serkland, Darwin K. (Albuquerque, NM); Olsson, III, Roy H. (Albuquerque, NM)

2010-12-28T23:59:59.000Z

330

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

331

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

332

A 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 to a high voltage transformer having outer taps and a center tap for stepping up the voltage of the alternating currentThe center tap of the tmsformer 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 ftwsformer. 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, J.R.

1993-12-31T23:59:59.000Z

333

Orographic Influences on the Distribution and Generation of Atmospheric Variability in a GCM  

Science Conference Proceedings (OSTI)

The effect of large-scale mountains on atmospheric variability is studied in a series of GCM experiments in which a single mountain is varied in height from 0 to 4 km. High-frequency (? 30 days) variability are ...

Jin-Yi Yu; Dennis L. Hartmann

1995-07-01T23:59:59.000Z

334

Reconstructing the NH Mean Temperature: Can Underestimation of Trends and Variability Be Avoided?  

Science Conference Proceedings (OSTI)

There are indications that hemispheric-mean climate reconstructions seriously underestimate the amplitude of low-frequency variability and trends. Some of the theory of linear regression and error-in-variables models is reviewed to identify the ...

Bo Christiansen

2011-02-01T23:59:59.000Z

335

Intraseasonal variability of the west African monsoon and African easterly waves during boreal summer.  

E-Print Network (OSTI)

??Substantial subseasonal variability in African easterly wave (AEW) activity and cyclogenesis frequency occurs in the main hurricane development region of the Atlantic during boreal summer.… (more)

Alaka, Ghassan J.

2010-01-01T23:59:59.000Z

336

Minimum Energy Compensation Strategy and Characteristic Analysis for Dynamic Voltage Restorer  

Science Conference Proceedings (OSTI)

The minimum energy compensation strategy and its characteristic for Dynamic Voltage Restorer (DVR) considering the equipment’s voltage limitation are discussed. The strategy when the injection voltage is under or especially above the voltage limitation ... Keywords: dynamic voltage restorer, minimum energy compensation, compensation strategy, compensation characteristic, voltage limitation

Yingying Liu; Xu Yonghai; Xiao Xiangning; Guo Chunlin

2009-10-01T23:59:59.000Z

337

Research on the SPLL based single phase voltage sag detection technique  

Science Conference Proceedings (OSTI)

The drop of voltage amplitude and the jump of phase angle are two important parameters of the voltage sag. The design of Dynamic Voltage Restorer (DVR) compensation voltage with voltage sag parameters is discussed and a single-phase sag parameter detection ... Keywords: SPLL, detection, single-phase, voltage sag

Xie Yue; Chen Le; Sun Jian; Gong Xu

2008-04-01T23:59:59.000Z

338

Planar LTCC transformers for high voltage flyback converters.  

SciTech Connect

This paper discusses the design and use of low-temperature (850 C to 950 C) co-fired ceramic (LTCC) planar magnetic flyback transformers for applications that require conversion of a low voltage to high voltage (> 100V) with significant volumetric constraints. Measured performance and modeling results for multiple designs showed that the LTCC flyback transformer design and construction imposes serious limitations on the achievable coupling and significantly impacts the transformer performance and output voltage. This paper discusses the impact of various design factors that can provide improved performance by increasing transformer coupling and output voltage. The experiments performed on prototype units demonstrated LTCC transformer designs capable of greater than 2 kV output. Finally, the work investigated the effect of the LTCC microstructure on transformer insulation. Although this paper focuses on generating voltages in the kV range, the experimental characterization and discussion presented in this work applies to designs requiring lower voltage.

Schofield, Daryl (NASCENT Technology Inc. , Watertown, SD); Schare, Joshua M.; Glass, Sarah Jill; Roesler, Alexander William; Ewsuk, Kevin Gregory; Slama, George (NASCENT Technology Inc. , Watertown, SD); Abel, Dave (NASCENT Technology Inc. , Watertown, SD)

2007-06-01T23:59:59.000Z

339

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

340

Sequential circuit design for radiation hardened multiple voltage integrated circuits  

DOE Patents (OSTI)

The present invention includes a radiation hardened sequential circuit, such as a bistable circuit, flip-flop or other suitable design that presents substantial immunity to ionizing radiation while simultaneously maintaining a low operating voltage. In one embodiment, the circuit includes a plurality of logic elements that operate on relatively low voltage, and a master and slave latches each having storage elements that operate on a relatively high voltage.

Clark, Lawrence T. (Phoenix, AZ); McIver, III, John K. (Albuquerque, NM)

2009-11-24T23:59:59.000Z

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

Waveform Characteristics of Voltage Sags: Definition and Algorithm Development  

Science Conference Proceedings (OSTI)

Voltage disturbances lasting more than one cycle are normally characterized in terms of voltage magnitude and event duration. These parameters provide an easily understood means of characterizing these types of voltage disturbances. However, magnitude and duration are not the only characteristics that affect loads. Many types of loads, such as contactors, control systems, and ac/dc drives, are also affected by other factors, such as the waveshape, the point in the waveform at which the disturbance begins...

1999-08-05T23:59:59.000Z

342

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

343

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

344

High Voltage Electric Discharge Consolidation of Tantalum Powders  

Science Conference Proceedings (OSTI)

Abstract Scope, The high voltage electric discharge consolidation (HVEDC) is a promising method of the volumetric-porous body manufacturing, which can be ...

345

The Current-voltage Characteristics of Grain Boundaries in Ionic ...  

Science Conference Proceedings (OSTI)

Presentation Title, The Current-voltage Characteristics of Grain Boundaries in Ionic ... A High-temperature Mössbauer Study of Iron-doped Ruddlesden-popper  ...

346

(SPS) and High Voltage Electric Discharge Consolidation (HVEDC  

Science Conference Proceedings (OSTI)

Presentation Title, Inter-Particle Contact Phenomena in Spark-Plasma Sintering ( SPS) and High Voltage Electric Discharge Consolidation (HVEDC). Author(s) ...

347

Spark-plasma Sintering vs. High Voltage Electric Discharge ...  

Science Conference Proceedings (OSTI)

High voltage electric discharge consolidation (HVEDC) includes high axial pressure and discharge of the electrical energy stored in capacitors, thus enabling a ...

348

Voltage Controlled Creep of a Nanoporous Gold/Electrolyte Hybrid ...  

Science Conference Proceedings (OSTI)

And the creep rate can also be controlled by the voltage (electrochemical ... CNT Reinforced Copper Composite for High Contact Pressure Electrodes by ...

349

(SPS) and High Voltage Electric Discharge Consolidation (HVEDC)  

Science Conference Proceedings (OSTI)

Presentation Title, Local Heat Balance in Spark-plasma Sintering (SPS) and High Voltage Electric Discharge Consolidation (HVEDC). Author(s), Eugene ...

350

Road to AC Voltage Standard Leads to Important Junction  

Science Conference Proceedings (OSTI)

Road to AC Voltage Standard Leads to Important Junction. ... Grumman in the mid-1990s.*** A number of innovations since then have led to the first ...

2013-08-13T23:59:59.000Z

351

Chronic Benzodiazepine Administration Potentiates High Voltage-Activated Calcium Currents  

E-Print Network (OSTI)

.aspetjournals.orgDownloadedfrom #12;other drugs of abuse has been reported to enhance high voltage-activated calcium channels (HVAs

Brand, Paul H.

352

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 ...

353

Energy-Big voltage, little package... | ornl.gov  

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

News DOE Pulse Media Contacts Media Mentions RSS Feeds News Home | ORNL | News | Story Tips SHARE Energy-Big voltage, little package Oak Ridge National Laboratory's new Stinger...

354

Specifying a Low-Voltage Dynamic Sag Corrector  

Science Conference Proceedings (OSTI)

Voltage sags are the most frequent and costly of power quality problems for industrial customers. A number of non-battery-based technologies have emerged in the market to mitigate the effects of voltage sags on industrial processes. Among these, the low-voltage dynamic sag corrector (DySC) can provide ride-through during sags to 50 percent of nominal voltage for up to 12 cycles with no energy storage; for longer ride-through or deeper sags, energy storage capacitors are available as an option. This repor...

2000-11-07T23:59:59.000Z

355

A Step Towards Energy-Efficient Voltage Control of Magnetic ...  

Science Conference Proceedings (OSTI)

... By combining these two types of materials, it is possible to create low ... by electric fields (applied voltage) instead of less energy-efficient magnetic ...

2013-07-30T23:59:59.000Z

356

Medium Voltage Cable Aging Management Guide, Revision 1  

Science Conference Proceedings (OSTI)

Medium-voltage cables (5- to 35-kV rated cables) have provided reasonable service in nuclear power plants. However, there is a concern that cables that have experienced long periods of wet service might degrade and fail in service. Because most plants have had few problems with medium-voltage cable, little on-staff experience with medium-voltage cables exists at most sites. This report has been prepared to provide information that will be of practical use when questions concerning medium-voltage cable lo...

2010-11-29T23:59:59.000Z

357

Operating standby redundant controller to improve voltage source inverter reliability .  

E-Print Network (OSTI)

??This thesis presents a control architecture that achieves operating standby redundancy for a voltage source inverter controller. The system was designed to increase reliability by… (more)

Blevins, Stephen T.

2007-01-01T23:59:59.000Z

358

California ISO Real-Time Voltage Security Assessment (VSA) Project...  

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

Arnold Schwarzenegger Governor REAL-TIME GRID RELIABILITY MANAGEMENT California ISO Real-Time Voltage Security Assessment (VSA) Project: Summary of Survey Results on Methodologies...

359

Patents and Perspective on Surge Protection for Low-Voltage ...  

Science Conference Proceedings (OSTI)

... In a high-voitage inverter the impedance is a resistor functioning to dampen voltage o\\ershoots and to im- plement a relay or solid state second ...

2013-05-17T23:59:59.000Z

360

Surge Protection in Low-Voltage AC Power Circuits  

Science Conference Proceedings (OSTI)

Surge Protection in Low-Voltage AC Power Circuits: An 8-part Anthology ... converting old and yellowing papers into 21st Century electronic files, and ...

2013-05-20T23:59:59.000Z

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.


361

Power frequency communication on long feeders and high levels of harmonic distortion  

SciTech Connect

TWACS is a unique Power Frequency Communication (PFC) technology. The power voltage is modulated at the substation bus for outbound communication and inbound communication from a remote transponder is accomplished by drawing precisely controlled current pulses which are detectable at the distribution substation. The propagation characteristics of the TWACS signal and the frequency characteristics of the signal detector make it possible to communicate over very long distribution feeders and provide a high degree of immunity against harmonic distortions of the power system voltage and current.

Mak, S.T.; Maginnis, R.L. [Distribution Control Systems, Inc., Hazelwood, MO (United States)

1995-10-01T23:59:59.000Z

362

Voltage Unbalance: Power Quality Issues, Related Standards and Mitigation Techniques: Effect of Unbalanced Voltage on End Use Equipm ent Performance  

Science Conference Proceedings (OSTI)

Unbalanced voltages can result in adverse effects on equipment and the electric distribution system. Under unbalanced conditions the distribution system will incur more losses and heating effects, and be less stable. The effect of voltage unbalance can also be detrimental to equipment such as induction motors, power electronic converters, and adjustable speed drives (ASDs). The purpose of this study is to investigate the causes and effects of voltage unbalance as well as the related standards and mitigat...

2000-06-21T23:59:59.000Z

363

Transmission gates combined with level-restoring CMOS gates reduce glitches in low-power low-frequency multipliers  

Science Conference Proceedings (OSTI)

Various 16-bit multiplier architectures are compared in terms of dissipated energy, propagation delay, energy-delay product (EDP), and area occupation, in view of low-power low-voltage signal processing for low-frequency applications. A novel practical ... Keywords: arithmetic, glitch, low frequency, low power, multiplier, switching activity, transmission gate

Flavio Carbognani; Felix Buergin; Norbert Felber; Hubert Kaeslin; Wolfgang Fichtner

2008-07-01T23:59:59.000Z

364

Local Dynamic Reactive Power for Correction of System Voltage Problems  

SciTech Connect

Distribution systems are experiencing outages due to a phenomenon known as local voltage collapse. Local voltage collapse is occurring in part because modern air conditioner compressor motors are much more susceptible to stalling during a voltage dip than older motors. These motors can stall in less than 3 cycles (.05s) when a fault, such as on the sub-transmission system, causes voltage to sag to 70 to 60%. The reasons for this susceptibility are discussed in the report. During the local voltage collapse, voltages are depressed for a period of perhaps one or two minutes. There is a concern that these local events are interacting together over larger areas and may present a challenge to system reliability. An effective method of preventing local voltage collapse is the use of voltage regulation from Distributed Energy Resources (DER) that can supply or absorb reactive power. DER, when properly controlled, can provide a rapid correction to voltage dips and prevent motor stall. This report discusses the phenomenon and causes of local voltage collapse as well as the control methodology we have developed to counter voltage sag. The problem is growing because of the use of low inertia, high efficiency air conditioner (A/C) compressor motors and because the use of electric A/C is growing in use and becoming a larger percentage of system load. A method for local dynamic voltage regulation is discussed which uses reactive power injection or absorption from local DER. This method is independent, rapid, and will not interfere with conventional utility system voltage control. The results of simulations of this method are provided. The method has also been tested at the ORNL s Distributed Energy Communications and Control (DECC) Laboratory using our research inverter and synchronous condenser. These systems at the DECC Lab are interconnected to an actual distribution system, the ORNL distribution system, which is fed from TVA s 161kV sub-transmission backbone. The test results are also provided and discussed. The simulations and testing show that local voltage control from DER can prevent local voltage collapse. The results also show that the control can be provided so quickly, within 0.5 seconds, that is does not interfere with conventional utility methods.

Kueck, John D [ORNL; Rizy, D Tom [ORNL; Li, Fangxing [ORNL; Xu, Yan [ORNL; Li, Huijuan [University of Tennessee, Knoxville (UTK); Adhikari, Sarina [ORNL; Irminger, Philip [ORNL

2008-12-01T23:59:59.000Z

365

Frequency Regulation Basics and Trends  

DOE Green Energy (OSTI)

The electric power system must address two unique requirements: the need to maintain a near real-time balance between generation and load, and the need to adjust generation (or load) to manage power flows through individual transmission facilities. These requirements are not new: vertically integrated utilities have been meeting them for a century as a normal part of conducting business. With restructuring, however, the services needed to meet these requirements, now called ''ancillary services'', are being more clearly defined. Ancillary services are those functions performed by the equipment and people that generate, control, and transmit electricity in support of the basic services of generating capacity, energy supply, and power delivery. The Federal Energy Regulatory Commission (FERC) has defined such services as those ''necessary to support the transmission of electric power from seller to purchaser given the obligations of control areas and transmitting utilities within those control areas to maintain reliable operations of the interconnected transmission system''. This statement recognizes the importance of ancillary services for both bulk-power reliability and support of commercial transactions. Balancing generation and load instantaneously and continuously is difficult because loads and generators are constantly fluctuating. Minute-to-minute load variability results from the random turning on and off of millions of individual loads. Longer-term variability results from predictable factors such as the daily and seasonal load patterns as well as more random events like shifting weather patterns. Generators also introduce unexpected fluctuations because they do not follow their generation schedules exactly and they trip unexpectedly due to a range of equipment failures. The output from wind generators varies with the wind. Storage technologies should be ideal suppliers of several ancillary services, including regulation, contingency reserves (spinning reserve, supplemental reserve, replacement reserve), and voltage support. These services are not free; in regions with energy markets, generators are paid to supply these services. In vertically integrated utilities (without energy markets) the utility incurs significant costs to supply these services. Supplying these services may be a significant business opportunity for emerging storage technologies. This report briefly explores the various ancillary services that may be of interest to storage. It then focuses on regulation, the most expensive ancillary service. It also examines the impact that increasing amounts of wind generation may have on regulation requirements, decreasing conventional regulation supplies, and the implications for energy storage.

Kirby, BJ

2005-05-06T23:59:59.000Z

366

VARIABLE TIME DELAY MEANS  

DOE Patents (OSTI)

An electrically variable time delay line is described which may be readily controlled simuitaneously with variable impedance matching means coupied thereto such that reflections are prevented. Broadly, the delay line includes a signal winding about a magnetic core whose permeability is electrically variable. Inasmuch as the inductance of the line varies directly with the permeability, the time delay and characteristic impedance of the line both vary as the square root of the permeability. Consequently, impedance matching means may be varied similariy and simultaneously w:th the electrically variable permeability to match the line impedance over the entire range of time delay whereby reflections are prevented.

Clemensen, R.E.

1959-11-01T23:59:59.000Z

367

A Multiphase, Modular, Bidirectional, Triple-Voltage DC-DC Converter Power Systems  

Science Conference Proceedings (OSTI)

Electrical power systems in future hybrid and fuel cell vehicles may employ three voltage [14 V, 42 V, and high voltage (HV)] nets. These will be necessary to accommodate existing 14-V loads as well as efficiently handle new heavy loads at the 42-V net and a traction drive on the HV bus. A low-cost DC-DC converter was proposed for connecting the three voltage nets. It minimizes the number of switches and their associated gate driver components by using two half-bridges and a high-frequency transformer. Another salient feature is that the half bridge on the 42-V bus is also utilized to provide the 14-V bus by operating at duty ratios around an atypical value of 1/3. Moreover, it makes use of the parasitic capacitance of the switches and the transformer leakage inductance for soft switching. The use of half bridges makes the topology well suited for interleaved multiphase modular configurations as a means to increase the power level because the capacitor legs can be shared. This paper presents simulation and experimental results on an interleaved two-phase arrangement rated at 4.5 kW. Also discussed are the benefits of operating with an atypical duty ratio on the transformer and a preferred multiphase configuration to minimize capacitor ripple currents.

Su, Gui-Jia [ORNL; Tang, Lixin [ORNL

2008-01-01T23:59:59.000Z

368

UPGRADING THE CEBAF INJECTOR WITH A NEW BOOSTER, HIGHER VOLTAGE GUN, AND HIGHER FINAL ENERGY  

Science Conference Proceedings (OSTI)

The Continuous Electron Beam Accelerator Facility (CEBAF) accelerator at Jefferson Lab will be upgraded from 6 GeV to 12 GeV in the next few years. To meet the requirement of the new machine and to take the opportunity to improve the beam quality, the CEBAF injector will be upgraded with a higher voltage gun, a new booster, and a new accelerating RF module. The CEBAF injector creates and accelerates three beams at different currents simultaneously. The beams are interleaved, each at one third of the RF frequency, traveling through the same beam line. The higher voltage gun will lower the space charge effects. The new booster with optimized beam dynamics will complete the bunching process and provide initial acceleration matched to the new gun voltage. Using our latest SRF design, the new booster has significantly lower x/y coupling effects that should improve our beam setup and operation for the highly sensitive parity experiments scheduled for the CEBAF's future. Finally, the new accelerating RF module will roughly double the injector final energy to match the rest of the 12 GeV accelerator. In this paper we will provide more detail about this upgrade.

Reza Kazimi, Arne Freyberger, Alicia Hofler, Andrew Hutton, Fay Hannon

2012-07-01T23:59:59.000Z

369

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

Science Conference Proceedings (OSTI)

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

370

Robust Design of Basic Low Voltage CMOS Transconductors  

Science Conference Proceedings (OSTI)

Two new low voltage transconductors are introduced and the statistical design of these transconductors are presented. The circuits operate in the saturation region with fully balanced input signals. Initial circuit simulation results are given. Response surface ... Keywords: design of experiments, low voltage, response surface methodology, roboust design, yield enhancement

Tuna B. Tarim; H. Hakan Kuntman; Mohammed Ismail

1999-09-01T23:59:59.000Z

371

Motor voltage asymmetry influence to the efficient energy usage  

Science Conference Proceedings (OSTI)

Analysis of the effect of unbalanced voltages on the three-phase induction motor is presented in the paper. Since the unbalanced voltage of 2%, 3.5% and 5% increase in losses could reach, in the same order, the amount of 8%, 25% and 50% of nominal power ... Keywords: asymetry, energy efficiency, induction motor, power losses, standard

Miloje Kostic; Aleksandar Nikolic

2010-07-01T23:59:59.000Z

372

Analysis of Voltage Notching Concerns at a Petroleum Pumping Station  

Science Conference Proceedings (OSTI)

This report presents the results of a voltage notching investigation at a petroleum pumping station. The analysis in this paper focuses on a particular example system where the voltage notching caused significant oscillations at the distribution system level, resulting in equipment problems at another customer supplied from the same system.

2003-12-31T23:59:59.000Z

373

Compile-time dynamic voltage scaling settings: opportunities and limits  

Science Conference Proceedings (OSTI)

With power-related concerns becoming dominant aspects of hardware and software design, significant research effort has been devoted towards system power minimization. Among run-time power-management techniques, dynamic voltage scaling (DVS) has emerged ... Keywords: analytical model, compiler, dynamic voltage scaling, low power, mixed-integer linear programming

Fen Xie; Margaret Martonosi; Sharad Malik

2003-06-01T23:59:59.000Z

374

Real-time static voltage scaling on multiprocessors  

Science Conference Proceedings (OSTI)

We propose a real-time static voltage scaling (RT-SVS) technique called T-L plane transforming, which is an extension of LLREF, an optimal real-time scheduling algorithm for multiprocessor systems. We present two RT-SVS algorithms for different types ... Keywords: energy consumption, multiprocessor systems, real-time scheduling, real-time voltage scaling

Kenji Funaoka; Shinpei Kato; Nobuyuki Yamasaki

2007-11-01T23:59:59.000Z

375

Proceedings: EPRI/NERC Forum on Voltage Stability  

Science Conference Proceedings (OSTI)

As power systems are operated at increased stress, utilities are becoming more concerned about voltage collapse and consequent severe disruptions. This meeting, cosponsored by EPRI and NERC, provided a forum for a group of international experts to exchange information on voltage stability, including its physical understanding, operational practices, and application of available tools.

1993-06-01T23:59:59.000Z

376

Wind Farm Grid Voltage Stability Researching Based on Cascade STATCOM  

Science Conference Proceedings (OSTI)

Though most wind turbine use induction generator, when wind induction generator with power generation, it will produce a series of power quality problems such as voltage fluctuations. This paper discusses the mathematical model of the wind induction ... Keywords: Wind induction generator, Cascade STATCOM, Wind farm, Voltage stability

Li Shengqing, Xu Wenxiang, Li Weizhou, Zeng Huanyue

2013-01-01T23:59:59.000Z

377

Rapid Oscillations in Cataclysmic Variables  

E-Print Network (OSTI)

I give an overview of the rich phenomenology of dwarf nova oscillations (DNOs) and Quasi-periodic Oscillations (QPOs) observed in cataclysmic variable stars (CVs). The favoured interpretation of these rapid brightness modulations (3 - >1000 s time scales) is that they are magnetic in nature - magnetically channelled accretion from the inner accretion disc for DNOs and possible magnetically excited travelling waves in the disc for QPOs. There is increasing evidence for the magnetic aspects, which extend to lower field the well known properties of strong field (polars) and intermediate strength field (intermediate polars) CVs. The result is that almost all CVs show the presence of magnetic fields on their white dwarf primaries - though for many the intrinsic field may be locally enhanced by the accretion process itself. There are many parallel behaviours with the QPOs seen in X-Ray binaries, with high and low frequency X-Ray QPOs resembling respectively the DNOs and QPOs in CVs.

Brian Warner

2003-12-06T23:59:59.000Z

378

Reactive Power Management to Address Short-Term Voltage Stability Using Optimal Reactive Power Allocation Method  

Science Conference Proceedings (OSTI)

Voltage stability has attracted attention recently because power systems are increasingly operated under heavy loads and subjected to high levels of dynamic fast acting loads. Voltage instability under these conditions can be manifested as depressed voltage profiles, delayed voltage recovery at load buses following a major disturbance, and even fast voltage collapse. Single-phase, low-inertia induction motors can have adverse effect on voltage stability as they decelerate in the event of voltage ...

2012-11-28T23:59:59.000Z

379

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

380

Living and Working Safely Around High-Voltage Power Lines.  

Science Conference Proceedings (OSTI)

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

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

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

382

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

E-Print Network (OSTI)

on the low voltage ride through (LVRT) capability of the doubly fed induction generator (DFIG) is also) controller to mitigate the effects of these faults is proposed. The DFIG compliance with numerous and compared. Simulation results indicate that these types of faults have a severe impact on the DFIG voltage

Pota, Himanshu Roy

383

Determination of the cathode and anode voltage drops in high power low-pressure amalgam lamps  

Science Conference Proceedings (OSTI)

For the first time, cathode and anode drops of powerful low-pressure amalgam lamps were measured. The lamp discharge current is 3.2 A, discharge current frequency is 43 kHz, linear electric power is 2.4 W/cm. The method of determination of a cathode drop is based on the change of a lamp operating voltage at variation of the electrode filament current at constant discharge current. The total (cathode plus anode) drop of voltage was measured by other, independent ways. The maximum cathode fall is 10.8 V; the anode fall corresponding to the maximal cathode fall is 2.4 V. It is shown that in powerful low pressure amalgam lamps the anode fall makes a considerable contribution (in certain cases, the basic one) to heating of electrodes. Therefore, the anode fall cannot be neglected, at design an electrode and ballast of amalgam lamps with operating discharge current frequency of tens of kHz.

Vasilyak, L. M., E-mail: vasilyak@ihed.ras.ru [Russian Academy of Sciences, Joint Institute for High Temperatures (Russian Federation); Vasiliev, A. I., E-mail: vasiliev@npo.lit.ru; Kostyuchenko, S. V.; Sokolov, D. V.; Startsev, A. Yu. [Joint Stock Company NPO LIT (Russian Federation); Kudryavtsev, N. N. [Moscow Institute of Physics and Technology (State University) (Russian Federation)

2011-12-15T23:59:59.000Z

384

Why inverse document frequency?  

Science Conference Proceedings (OSTI)

Inverse Document Frequency (IDF) is a popular measure of a word's importance. The IDF invariably appears in a host of heuristic measures used in information retrieval. However, so far the IDF has itself been a heuristic. In this paper, we show IDF to ...

Kishore Papineni

2001-06-01T23:59:59.000Z

385

A Survey on the Principle and Control of Dynamic Voltage Restorer  

Science Conference Proceedings (OSTI)

With the development of information and automation techniques, dynamic voltage problems are once again in the spotlight. Dynamic voltage restorer (DVR) is a modern and important custom power device used for mitigating voltage sags in power distribution ... Keywords: voltage sag, dynamic voltage restorer (DVR), control strategy, power quality, optimized compensation, energy storage

Shuhong Kong; Zhongdong Yin; Renzhong Shan; Weidong Shang

2009-10-01T23:59:59.000Z

386

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

387

A New Method of Identifying the Low Frequency Oscillations of Power Systems  

Science Conference Proceedings (OSTI)

To solve the order choice problem in Prony algorithm, active power or voltage signals are usually used by Prony algorithms based on singular values decomposition-total least square (SVD-TLS). Because of the difference in choosing the standard parameters ... Keywords: power systems, low frequency oscillations, improved Prony algorithm, SVD-TLS, DVR, SNR

Yishu Zhao; Yang Gao; Zhijian Hu; Yongjun Yang; Jie Zhan; Yan Zhang

2009-10-01T23:59:59.000Z

388

Design of a fast-settling OTA for high frequency switched-capacitor applications  

E-Print Network (OSTI)

The ever-growing technology has enabled switched-capacitor (SC) circuits to operate at the MHz frequency range. The equally increasing demand for high speed signal processing using SC technique dictates the need of high performance operational amplifiers (opamps). Low voltage and low poer operation, one of the main industrial trends, however, puts significant challenges to analog circuit designers. In current digital-dominant technology, CMOS devices have become more suitable for digital circuit design; they require lower operation voltage with threshold voltages decreasing relatively sluggish. Designers should still be able to design circuits with the same or better performance then circuits designed for larger power supplies. As more and more building blocks and systems are getting integrated into smaller area, they still must be designed to achieve the needs of portable, lighter and reliable product. In this thesis, characteristics of low voltage and low power SC circuits for high frequency applications are investigated. Several candidates of opamp architecture are compared in light of limitations aforementioned and design issues of selected topology are to be further examined. The proposed solution is designed at transistor level in Hewlett Packard 0.5 []m digital CMOS technology. As a test bench, a SC biquad band pass filter with sampling frequency of up to 120 MHz and center frequency of 20 MHz is designed and fabricated through MOSIS. Test results of fabricated IC's are presented and the validity of this research is accordingly justified.

Park, Jinki

2002-01-01T23:59:59.000Z

389

Estimated Global Hydrographic Variability  

Science Conference Proceedings (OSTI)

An estimate is made of the three-dimensional global oceanic temperature and salinity variability, omitting the seasonal cycle, both as a major descriptive element of the ocean circulation and for use in the error estimates of state estimation. ...

Gaël Forget; Carl Wunsch

2007-08-01T23:59:59.000Z

390

Understanding Biomass Feedstock Variability  

SciTech Connect

If the singular goal of biomass logistics and the design of biomass feedstock supply systems is to reduce the per ton supply cost of biomass, these systems may very well develop with ultimate unintended consequences of highly variable and reduced quality biomass feedstocks. This paper demonstrates that due to inherent species variabilities, production conditions, and differing harvest, collection, and storage practices, this is a very real scenario that biomass producers and suppliers as well as conversion developers should be aware of. Biomass feedstock attributes of ash, carbohydrates, moisture, and particle morphology will be discussed. We will also discuss specifications for these attributes, inherent variability of these attributes in biomass feedstocks, and approaches and solutions for reducing variability for improving feedstock quality.

Kevin L. Kenney; William A. Smith; Garold L. Gresham; Tyler L. Westover

2013-01-01T23:59:59.000Z

391

Testing requirements for variable-speed generating technology for wind turbine applications. Final report  

Science Conference Proceedings (OSTI)

Guidelines for evaluating the impacts of integrating variable-speed, constant-frequency (VSCF) wind turbines into electric utility systems have been proposed based upon prior test experiences with the NASA VSCF system and the expected performance of the Westinghouse and OMNION VSCF systems. The NASA and Westinghouse VSCF generating systems use a wound rotor induction generator and a cycloconverter, while the OMNION system uses a wound rotor induction generator and a dc-current link converter. The design of VSCF/utility system interface requirements and test plans is based on utility system electrical issues such as utility system control and operation, protection, voltage/reactive power management, power quality, and reliability. A framework for testing VSCF concepts is proposed which includes a three stage process: modeling of the system to analyze design alternatives and simulate disturbances that could be harmful to the actual system; laboratory testing which involves the use of the system under controlled conditions; and field testing to collect data under actual conditions to validate models and analyze the wind turbine behavior.

Herrera, J.I.

1986-05-01T23:59:59.000Z

392

Discrete pulse modulation strategies for high-frequency inverter systems  

SciTech Connect

High-performance high-frequency inverter systems for UPS applications represent a demanding application that cannot be easily realized using conventional hard-switched PWM inverter topologies. Adoption of typical soft-switched inverters such as the resonant dc link inverter require the use of discrete pulse modulation strategies. New controller structures are necessary to cope with stringent voltage regulation and distortion constraints in the presence of unbalanced and nonlinear loads. This paper presents a controller that utilizes load current feed-forward strategy with a cost function current regulator to achieve excellent transient performance characteristics. Voltage regulation is ensured using a synchronous frame regulator. Detailed simulation and experimental results verifying the concepts are presented. Although this paper focuses on soft-switching inverters, the control concepts can be applied to conventional hard-switching inverters as well.

Venkataramanan, G. (Montana State Univ., Bozeman, MT (United States). Dept. of Electrical Engineering); Divan, D.M. (Univ. of Wisconsin, Madison, WI (United States). Dept. of Electrical and Computer Engineering); Jahns, T.M. (General Electric Co., Schenectady, NY (United States))

1993-07-01T23:59:59.000Z

393

A Novel Dynamic Voltage Restorer with Outage Handling Capability Using Fuzzy Logic Controler  

Science Conference Proceedings (OSTI)

This paper presents a novel dynamic voltage restorer (DVR) capable of handling deep sags including outage on a low voltage distribution system. The DVR recovers sags up to 10% of nominal voltage; otherwise, it will operate as an uninterruptible power ...

M. Ashari; T. Hiyama; M. Pujiantara; H. Suryoatmojo; M. Hery Purnomo

2007-09-01T23:59:59.000Z

394

Fault Detection and Isolation in Low-Voltage DC Distribution ...  

A University of Colorado research team led by Jae-Do Park has developed a fault detection and isolation scheme for a low-voltage DC-bus microgrid system, ...

395

NIST Online Museum of Quantum Voltage Standards, 1970s  

Science Conference Proceedings (OSTI)

... Metrologists wondered if they could connect several junctions in series to make a larger voltage, just as a 12-volt car battery is made up of six 2-volt ...

2011-03-30T23:59:59.000Z

396

Fusing strategies for the dual-voltage fault  

E-Print Network (OSTI)

This thesis focuses on the 42V - 14V fault in a dual voltage system and discusses the possibility of effective fusing. A simple model for the system had been created from technical documentation. Based on the model and the ...

Shrivastava, Rupam, 1981-

2005-01-01T23:59:59.000Z

397

Functionalized High Voltage Spinel Composite for High Power ...  

Science Conference Proceedings (OSTI)

Recently, spinel LiNi0.5Mn1.5O4 with high working voltage and long cycle life makes it become the one of most promising cathode for high power delivery.

398

ESS 2012 Peer Review - Low Cost, Manufacturable High Voltage...  

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

Storage for Power Flow Management and Voltage Control on an 11kV UK Distribution Network", 20th International Conference on Electricity Distribution, June 2009. S1 S2 C1 C2...

399

Multilevel cascade voltage source inverter with seperate DC sources  

SciTech Connect

A multilevel cascade voltage source inverter having separate DC sources is described herein. This inverter is applicable to high voltage, high power applications such as flexible AC transmission systems (FACTS) including static VAR generation (SVG), power line conditioning, series compensation, phase shifting and voltage balancing and fuel cell and photovoltaic utility interface systems. The M-level inverter consists of at least one phase wherein each phase has a plurality of full bridge inverters equipped with an independent DC source. This inverter develops a near sinusoidal approximation voltage waveform with only one switching per cycle as the number of levels, M, is increased. The inverter may have either single-phase or multi-phase embodiments connected in either wye or delta configurations.

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

1997-01-01T23:59:59.000Z

400

Multilevel cascade voltage source inverter with seperate DC sources  

DOE Patents (OSTI)

A multilevel cascade voltage source inverter having separate DC sources is described herein. This inverter is applicable to high voltage, high power applications such as flexible AC transmission systems (FACTS) including static VAR generation (SVG), power line conditioning, series compensation, phase shifting and voltage balancing and fuel cell and photovoltaic utility interface systems. The M-level inverter consists of at least one phase wherein each phase has a plurality of full bridge inverters equipped with an independent DC source. This inverter develops a near sinusoidal approximation voltage waveform with only one switching per cycle as the number of levels, M, is increased. The inverter may have either single-phase or multi-phase embodiments connected in either wye or delta configurations.

Peng, Fang Zheng (Knoxville, TN); Lai, Jih-Sheng (Blacksburg, VA)

2002-01-01T23:59:59.000Z

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.


401

Design & Fabrication of a High-Voltage Photovoltaic Cell  

DOE Green Energy (OSTI)

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

402

Robust Design of Basic Low Voltage CMOS Transconductors  

Science Conference Proceedings (OSTI)

Two new low voltage transconductors are introduced and the statistical design of these transconductors are presented. The circuits operate in the saturation region with fully balanced input signals. Initial circuit simulation results are given. Response surface ...

Tuna B. Tarim; H. Hakan Kuntman; Mohammed Ismail

1999-09-01T23:59:59.000Z

403

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

404

High power impulse magnetron sputtering: Current-voltage-time ...  

pauses between pulses !typically 20 ms". The nominal volt-age of the pulser was adjustable up to 1000 V. The arc threshold was set to 120 A. If the current exceeded this

405

Planar LTCC transformers for high voltage flyback converters: Part II.  

Science Conference Proceedings (OSTI)

This paper is a continuation of the work presented in SAND2007-2591 'Planar LTCC Transformers for High Voltage Flyback Converters'. The designs in that SAND report were all based on a ferrite tape/dielectric paste system originally developed by NASCENTechnoloy, Inc, who collaborated in the design and manufacturing of the planar LTCC flyback converters. The output/volume requirements were targeted to DoD application for hard target/mini fuzing at around 1500 V for reasonable primary peak currents. High voltages could be obtained but with considerable higher current. Work had begun on higher voltage systems and is where this report begins. Limits in material properties and processing capabilities show that the state-of-the-art has limited our practical output voltage from such a small part volume. In other words, the technology is currently limited within the allowable funding and interest.

Schofield, Daryl (NASCENTechnology, Inc., Watertown, SD); Schare, Joshua M., Ph.D.; Slama, George (NASCENTechnology, Inc., Watertown, SD); Abel, David (NASCENTechnology, Inc., Watertown, SD)

2009-02-01T23:59:59.000Z

406

Multilevel cascade voltage source inverter with separate DC sources  

DOE Patents (OSTI)

A multilevel cascade voltage source inverter having separate DC sources is described herein. This inverter is applicable to high voltage, high power applications such as flexible AC transmission systems (FACTS) including static VAR generation (SVG), power line conditioning, series compensation, phase shifting and voltage balancing and fuel cell and photovoltaic utility interface systems. The M-level inverter consists of at least one phase wherein each phase has a plurality of full bridge inverters equipped with an independent DC source. This inverter develops a near sinusoidal approximation voltage waveform with only one switching per cycle as the number of levels, M, is increased. The inverter may have either single-phase or multi-phase embodiments connected in either wye or delta configurations. 15 figs.

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

1997-06-24T23:59:59.000Z

407

Time varying voltage combustion control and diagnostics sensor  

DOE Patents (OSTI)

A time-varying voltage is applied to an electrode, or a pair of electrodes, of a sensor installed in a fuel nozzle disposed adjacent the combustion zone of a continuous combustion system, such as of the gas turbine engine type. The time-varying voltage induces a time-varying current in the flame which is measured and used to determine flame capacitance using AC electrical circuit analysis. Flame capacitance is used to accurately determine the position of the flame from the sensor and the fuel/air ratio. The fuel and/or air flow rate (s) is/are then adjusted to provide reduced flame instability problems such as flashback, combustion dynamics and lean blowout, as well as reduced emissions. The time-varying voltage may be an alternating voltage and the time-varying current may be an alternating current.

Chorpening, Benjamin T. (Morgantown, WV); Thornton, Jimmy D. (Morgantown, WV); Huckaby, E. David (Morgantown, WV); Fincham, William (Fairmont, WV)

2011-04-19T23:59:59.000Z

408

Light Flicker in Compact Fluorescent Lamps Caused by Voltage Fluctuations  

Science Conference Proceedings (OSTI)

This power quality (PQ) case study presents tests performed at the EPRI Power Electronics Applications Center (PEAC) Power Quality Test Facility to characterize the light output of an incandescent lamp and compact fluorescent lamps during voltage fluctuations.

2003-12-31T23:59:59.000Z

409

Elevated Neutral to Earth and Contact Voltages in Distribution Systems  

Science Conference Proceedings (OSTI)

Perceptible voltage potentials at publicly and privately accessible human and animal contact locations pose concerns for utilities, regulators, and the public. Each year since 2004, EPRI research in this area has considered the most important concerns associated with these perceptible voltages by promoting consistent and repeatable assessment methodologies, sponsoring workshops, and creating a repository of case studies and general information. These and other project efforts are geared toward expediting...

2008-12-18T23:59:59.000Z

410

INTENSITY OF BETATRON RADIATION AS FUNCTION OF INJECTION VOLTAGE  

SciTech Connect

The intensity of betatron radiation emission as a function of injection voltage was studied using a 25-Mev betatron with a 350-kw external electron injector. The injection voltage was measured every 20 to 30 kw from 50 to 250 kw. The results showed that up to 250 kw, emission intensity increases according to theory. It is suggested that an increase in injection intensity up to 1000 kw and over should result in a considerable rise in emission intensity. (R.V.J.)

Moskalev, V.A.; Okulov, B.V.

1962-09-01T23:59:59.000Z

411

Chloromethyl chlorosulfate as a voltage delay inhibitor in lithium cells  

DOE Patents (OSTI)

Chloromethyl chlorosulfate (CMCS) is used as a passive film growth inhibitor in electrochemical cells to minimize voltage delay and low-voltage discharge. Film growth on lithium anodes is significantly diminished when CMCS is added to SOCl{sub 2} and SO{sub 2}Cl{sub 2} electrolytes of lithium batteries. The CMCS also has the effect of extending the shelf-life of Li/SOCl{sub 2} and Li/SO{sub 2}Cl{sub 2} batteries.

Delnick, F.M.

1991-04-05T23:59:59.000Z

412

Cable Aging Management Training Course for Low-Voltage Cables  

Science Conference Proceedings (OSTI)

The "EPRI PSE Cable Aging Training Course for Low-Voltage Cables" provides a basis for understanding of the aging of the insulation and jackets of electrical cables used in low-voltage systems. Practical techniques for determining which cables are prone to premature aging and for evaluating their condition are described. The course contains 11 modules. The first 9 modules describe the body of the cable aging management process. The last two modules, "Cable Failure Assessment" and "Performing a Walkdown o...

2003-11-24T23:59:59.000Z

413

Optical control system for high-voltage terminals  

DOE Patents (OSTI)

An optical control system for the control of devices in the terminal of an electrostatic accelerator includes a laser that is modulated by a series of preselected codes produced by an encoder. A photodiode receiver is placed in the laser beam at the high-voltage terminal of an electrostatic accelerator. A decoder connected to the photodiode decodes the signals to provide control impulses for a plurality of devices at the high voltage of the terminal.

Bicek, John J. (Tinley Park, IL)

1978-01-01T23:59:59.000Z

414

Chloromethyl chlorosulfate as a voltage delay inhibitor in lithium cells  

DOE Patents (OSTI)

Chloromethyl chlorosulfate (CMCS) is used as a passive film growth inhibitor in electrochemical cells to minimize voltage delay and low-voltage discharge. Film growth on lithium anodes is significantly diminished when CMCS is added to SOCl.sub.2 and SO.sub.2 Cl.sub.2 electrolytes of lithium batteries. The CMCS also has the effect of extending the shelf-life of Li/SOCl.sub.2 and Li/SO.sub.2 Cl.sub.2 batteries.

Delnick, Frank M. (Albuquerque, NM)

1993-01-01T23:59:59.000Z

415

Chloromethyl chlorosulfate as a voltage delay inhibitor in lithium cells  

DOE Patents (OSTI)

Chloromethyl chlorosulfate (CMCS) is used as a passive film growth inhibitor in electrochemical cells to minimize voltage delay and low-voltage discharge. Film growth on lithium anodes is significantly diminished when CMCS is added to SOCl[sub 2] and SO[sub 2]Cl[sub 2] electrolytes of lithium batteries. The CMCS also has the effect of extending the shelf-life of Li/SOCl[sub 2] and Li/SO[sub 2]Cl[sub 2] batteries.

Delnick, F.M.

1993-04-13T23:59:59.000Z

416

Measuring Helical FCG Voltage with an Electric Field Antenna  

SciTech Connect

A method of measuring the voltage produced by a helical explosive flux compression generator using a remote electric field antenna is described in detail. The diagnostic has been successfully implemented on several experiments. Measured data from the diagnostic compare favorably with voltages predicted using the code CAGEN, validating our predictive modeling tools. The measured data is important to understanding generator performance, and is measured with a low-risk, minimally intrusive approach.

White, A D; Anderson, R A; Javedani, J B; Reisman, D B; Goerz, D A; Ferriera, A J; Speer, R D

2011-08-01T23:59:59.000Z

417

High voltage series connected tandem junction solar battery  

DOE Patents (OSTI)

A high voltage series connected tandem junction solar battery which comprises a plurality of strips of tandem junction solar cells of hydrogenated amorphous silicon having one optical path and electrically interconnected by a tunnel junction. The layers of hydrogenated amorphous silicon, arranged in a tandem configuration, can have the same bandgap or differing bandgaps. The tandem junction strip solar cells are series connected to produce a solar battery of any desired voltage.

Hanak, Joseph J. (Lawrenceville, NJ)

1982-01-01T23:59:59.000Z

418

Design and Implementation of Switching Voltage Integrated Circuits Based on Sliding Mode Control  

E-Print Network (OSTI)

The need for high performance circuits in systems with low-voltage and low-power requirements has exponentially increased during the few last years due to the sophistication and miniaturization of electronic components. Most of these circuits are required to have a very good efficiency behavior in order to extend the battery life of the device. This dissertation addresses two important topics concerning very high efficiency circuits with very high performance specifications. The first topic is the design and implementation of class D audio power amplifiers, keeping their inherent high efficiency characteristic while improving their linearity performance, reducing their quiescent power consumption, and minimizing the silicon area. The second topic is the design and implementation of switching voltage regulators and their controllers, to provide a low-cost, compact, high efficient and reliable power conversion for integrated circuits. The first part of this dissertation includes a short, although deep, analysis on class D amplifiers, their history, principles of operation, architectures, performance metrics, practical design considerations, and their present and future market distribution. Moreover, the harmonic distortion of open-loop class D amplifiers based on pulse-width modulation (PWM) is analyzed by applying the duty cycle variation technique for the most popular carrier waveforms giving an easy and practical analytic method to evaluate the class D amplifier distortion and determine its specifications for a given linearity requirement. Additionally, three class D amplifiers, with an architecture based on sliding mode control, are proposed, designed, fabricated and tested. The amplifiers make use of a hysteretic controller to avoid the need of complex overhead circuitry typically needed in other architectures to compensate non-idealities of practical implementations. The design of the amplifiers based on this technique is compact, small, reliable, and provides a performance comparable to the state-of-the-art class D amplifiers, but consumes only one tenth of quiescent power. This characteristic gives to the proposed amplifiers an advantage for applications with minimal power consumption and very high performance requirements. The second part of this dissertation presents the design, implementation, and testing of switching voltage regulators. It starts with a description and brief analysis on the power converters architectures. It outlines the advantages and drawbacks of the main topologies, discusses practical design considerations, and compares their current and future market distribution. Then, two different buck converters are proposed to overcome the most critical issue in switching voltage regulators: to provide a stable voltage supply for electronic devices, with good regulation voltage, high efficiency performance, and, most important, a minimum number of components. The first buck converter, which has been designed, fabricated and tested, is an integrated dual-output voltage regulator based on sliding mode control that provides a power efficiency comparable to the conventional solutions, but potentially saves silicon area and input filter components. The design is based on the idea of stacking traditional buck converters to provide multiple output voltages with the minimum number of switches. Finally, a fully integrated buck converter based on sliding mode control is proposed. The architecture integrates the external passive components to deliver a complete monolithic solution with minimal silicon area. The buck converter employs a poly-phase structure to minimize the output current ripple and a hysteretic controller to avoid the generation of an additional high frequency carrier waveform needed in conventional solutions. The simulated results are comparable to the state-of-the-art works even with

Rojas Gonzalez, Miguel Angel

2009-08-01T23:59:59.000Z

419

Low-voltage, low-power circuits for data communication systems  

E-Print Network (OSTI)

There are growing industrial demands for low-voltage supply and low-power consumption circuits and systems. This is especially true for very high integration level and very large scale integrated (VLSI) mixed-signal chips and system-on-a-chip. It is mainly due to the limited power dissipation within a small area and the costs related to the packaging and thermal management. In this research work, two low-voltage, low-power integrated circuits used for data communication systems are introduced. The first one is a high performance continuous-time linear phase filter with automatic frequency tuning. The filter can be used in hard disk driver systems and wired communication systems such as 1000Base-T transceivers. A pseudo-differential operational transconductance amplifier (OTA) based on transistors operating in triode region is used to achieve a large linear signal swing with low-voltage supplies. A common-mode (CM) control circuit that combines common-mode feedback (CMFB), common-mode feedforward (CMFF), and adaptive-bias has been proposed. With a 2.3V single supply, the filter?s total harmonic distortion is less than ?44dB for a 2VPP differential input, which is due to the well controlled CM behavior. The ratio of the root mean square value of the ac signal to the power supply voltage is around 31%, which is much better than previous realizations. The second integrated circuit includes two LVDS drivers used for high-speed point-to-point links. By removing the stacked switches used in the conventional structures, both LVDS drivers can operate with ultra low-voltage supplies. Although the Double Current Sources (DCS) LVDS driver draws twice minimum static current as required by the signal swing, it is quite simple and achieves very high speed operation. The Switchable Current Sources (SCS) LVDS driver, by dynamically switching the current sources, draws minimum static current and reduces the power consumption by 60% compared to the previously reported LVDS drivers. Both LVDS drivers are compliant to the standards and operate at data rates up to gigabits-per-second.

Chen, Mingdeng

2003-12-01T23:59:59.000Z

420

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

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

Voltage stability limits for weak power systems with high wind penetration.  

E-Print Network (OSTI)

??Analysis of power system voltage stability has practical value in increasing wind penetration levels. As wind penetration levels increase in power systems, voltage stability challenges… (more)

Tamimi, Ala

2011-01-01T23:59:59.000Z

422

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

423

Georeactor Variability and Integrity  

E-Print Network (OSTI)

As a deep-Earth energy source, the planetocentric nuclear-fission georeactor concept is on a more secure scientific footing than the previous idea related to the assumed growth of the inner core. Unlike previously considered deep-Earth energy sources, which are essentially constant on a human time-scale, variability in nuclear fission reactors can arise from changes in composition and/or position of fuel, moderators, and neutron absorbers. Tantalizing circumstantial evidence invites inquiry into the possibility of short-term planetocentric nuclear fission reactor variability. This brief communication emphasizes the importance of scientific integrity and highlights the possibility of variable georeactor power output so that these might be borne in mind in future investigations, especially those related to the Earth's heat flux.

J. Marvin Herndon

2005-10-04T23:59:59.000Z

424

Georeactor Variability and Integrity  

E-Print Network (OSTI)

As a deep-Earth energy source, the planetocentric nuclear-fission georeactor concept is on a more secure scientific footing than the previous idea related to the assumed growth of the inner core. Unlike previously considered deep-Earth energy sources, which are essentially constant on a human time-scale, variability in nuclear fission reactors can arise from changes in composition and/or position of fuel, moderators, and neutron absorbers. Tantalizing circumstantial evidence invites inquiry into the possibility of short-term planetocentric nuclear fission reactor variability. This brief communication emphasizes the importance of scientific integrity and highlights the possibility of variable georeactor power output so that these might be borne in mind in future investigations, especially those related to the Earth's heat flux.

Herndon, J M

2005-01-01T23:59:59.000Z

425

Design of a variable gain amplifier for an ultrawideband receiver  

E-Print Network (OSTI)

A fully differential CMOS variable gain amplifier (VGA) has been designed for an ultra-wideband receiver. The VGA comprises of two variable gain stages followed by a post amplifier stage. The interface between the digital control block and the analog VGA is formed by a digital-to-analog converter and an exponential voltage generator. The gain of the VGA varies dB-linearly from 0 to 52 dB with respect to the control voltage. The VGA is operated in open loop with a bandwidth greater than 500 MHz throughout the gain range to cater to the requirements of the ultra-wideband system. The noise-to-power ratio of the VGA is -23.9 dB for 1Vp-p differential input signal in the low gain setting, and the equivalent input referred noise is 1.01 V2 for the high gain setting. All three stages use common mode feedback to fix and stabilize the output DC levels at a particular voltage depending on the input common-mode requirement of the following stage. DC offset cancellation has also been incorporated to minimize the input referred DC offset caused by systematic and random mismatches in the circuit. Compensation schemes to minimize the effects of temperature, supply and process variations have been included in the design. The circuit has been designed in 0.18??m CMOS technology, and the post layout simulations are in good agreement with the schematic simulations.

Krishnanji, Sivasankari

2005-08-01T23:59:59.000Z

426

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

Science Conference Proceedings (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)

2013-01-01T23:59:59.000Z

427

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

428

Laser-frequency multiplication  

SciTech Connect

A high quality mode locked pulse train was obtained at 9.55 micrometers, the CO2 wavelength chosen for frequency doubling into the atmospheric window at 4.8 micrometers. The pulse train consists of a 3 micro sec burst of 1.5 nsec pulses separated by 40 nsec, in a TEM(00) mode and with a total energy of 100 mJ. The pulse intensity without focussing is about 3 MW/sq.cm., already quite close to the target intensity of 10 MW/sq.cm. for frequency doubling in a AgGaSe2 crystal. The mode-locked train is obtained by intracavity modulation at 12.5 MHz using a germanium crystal driven with a power of about 30 Watts. Line selection is achieved firstly by the use of a 0.92 mm thick CaF2 plate at the Brewster angle within the cavity, which completely suppresses 10.6 micrometer band radiation. Secondly, a particular rotational line, the P20 at 9.55 micrometers, is selected by the injection of a continuous beam is mode-matched to the pulsed laser cavity using a long focal length lens, and for best line-locking it is necessary to fine tune the length of the pulsed laser resonator. Injection causes substantial depression of the gain switched spike.

Not Available

1991-11-01T23:59:59.000Z

429

Modeling 18° Water Variability  

Science Conference Proceedings (OSTI)

Variability of 18° Water formation is investigated with an isopycnic-coordinate model of the North Atlantic. A 30-year spinup integration is used as a “control” experiment in which the upper water column in the Sargasso Sea is shown to be in ...

Robert Marsh; Adrian L. New

1996-06-01T23:59:59.000Z

430

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

431

Method and Appartus 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.

2005-01-18T23:59:59.000Z

432

The frequency dependent impedance of an HVdc converter  

Science Conference Proceedings (OSTI)

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)

1995-07-01T23:59:59.000Z

433

Animation of JILA Frequency Comb Spectroscopy Technique  

Science Conference Proceedings (OSTI)

Animation of JILA Frequency Comb Spectroscopy Technique. The new JILA "frequency comb spectroscopy" technique ...

2012-08-17T23:59:59.000Z

434

Frequency mixing crystal  

DOE Patents (OSTI)

In a laser system for converting infrared laser light waves to visible light comprising a source of infrared laser light waves and means of harmonic generation associated therewith for production of light waves at integral multiples of the frequency of the original wave, the improvement of said means of harmonic generation comprising a crystal having the chemical formula X{sub 2} Y(NO{sub 3}){sub 5} {center_dot} 2 nZ{sub 2}O wherein X is selected from the group consisting of Li, Na, K, Rb, Cs, and Tl; Y is selected from the group consisting of Sc, Y, La, Ce, Nd, Pr, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Al, Ga, and In; Z is selected from the group consisting of H and D; and n ranges from 0 to 4.

Ebbers, C.A.; Davis, L.E.; Webb, M.

1990-10-16T23:59:59.000Z

435

Frequency mixing crystal  

DOE Patents (OSTI)

In a laser system for converting infrared laser light waves to visible light comprising a source of infrared laser light waves and means of harmonic generation associated therewith for production of light waves at integral multiples of the frequency of the original wave, the improvement of said means of harmonic generation comprising a crystal having the chemical formula X{sub 2} Y(NO{sub 3}){sub 5} {center dot} 2 nZ{sub 2}O wherein X is selected from the group consisting of Li, Na, K, Rb, Cs, and Tl; Y is selected from the group consisting of Sc, Y, La, Ce, Nd, Pr, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Al, Ga, and In; Z is selected from the group consisting of H and D; and n ranges from 0 to 4.

Ebbers, C.A.; Davis, L.E.; Webb, M.

1990-10-16T23:59:59.000Z

436

Frequency mixing crystal  

DOE Patents (OSTI)

In a laser system for converting infrared laser light waves to visible light comprising a source of infrared laser light waves and means of harmoic generation associated therewith for production of light waves at integral multiples of the frequency of the original wave, the improvement of said means of harmonic generation comprising a crystal having the chemical formula X.sub.2 Y(NO.sub.3).sub.5 .multidot.2 nZ.sub.2 o wherein X is selected from the group consisting of Li, Na, K, Rb, Cs, and Tl; Y is selected from the group consisting of Sc, Y, La, Ce, Nd, Pr, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Al, Ga, and In; Z is selected from the group consisting of H and D; and n ranges from 0 to 4.

Ebbers, Christopher A. (Livermore, CA); Davis, Laura E. (Manteca, CA); Webb, Mark (Salida, CA)

1992-01-01T23:59:59.000Z

437

Interaction of Multiple Distributed Energy Resources in Voltage Regulation  

Science Conference Proceedings (OSTI)

Distributed energy resources (DE) with power electronics (PE) interfaces with the right control are capable of providing reactive power related ancillary services; voltage regulation in particular has drawn much attention. In this paper the problem of how to coordinate control multiple DEs to regulate the local voltage in the distribution system is addressed. A control method for voltage regulation using the DE PE controller is presented and based on the proposed control scheme; the voltage regulation of a distribution system with one DE and two DEs are tested, respectively. The factors affecting the gain parameters of the PE controller are investigated. The simulation results show that the parameters of the controller determine its dynamic response for voltage regulation and the factors associated with the network characteristics, such as locations of DEs and the amount of load, affect the impact range of the controller. The research work presented in this paper can be potentially used for the control system design of Smart Grid or Utility of the Future.

Li, Huijuan [University of Tennessee, Knoxville (UTK); Li, Fangxing [ORNL; Xu, Yan [ORNL; Rizy, D Tom [ORNL; Kueck, John D [ORNL

2008-01-01T23:59:59.000Z

438

Effect of voltage dynamics on response properties in a model of sensory hair cell  

E-Print Network (OSTI)

Sensory hair cells in auditory and vestibular organs rely on active mechanisms to achieve high sensitivity and frequency selectivity. Recent experimental studies have documented self-sustained oscillations in hair cells of lower vertebrates on two distinct levels. First, the hair bundle can undergo spontaneous mechanical oscillations. Second, somatic electric voltage oscillations across the baso-lateral membrane of the hair cell have been observed. We develop a biophysical model of the bullfrog's saccular hair cell consisting of two compartments, mechanical and electrical, to study how the mechanical and the voltage oscillations interact to produce coherent self-sustained oscillations and how this interaction contributes to the overall sensitivity and selectivity of the hair cell. The model incorporates nonlinear mechanical stochastic hair bundle system coupled bi-directionally to a Hodgkin-Huxley type system describing somatic ionic currents. We isolate regions of coherent spontaneous oscillations in the parameter space of the model and then study how coupling between compartments affect sensitivity of the hair cell to external mechanical perturbations. We show that spontaneous electrical oscillations may enhance significantly the sensitivity and selectivity of the hair cell.

Rami Amro; Alexander B. Neiman

2012-09-27T23:59:59.000Z

439

Active filters for high-voltage direct-current (HVDC) converter terminals: Final report  

SciTech Connect

This report evaluates the technical and economic feasibility for active filtering of dc-side voltage harmonics and the ac-side current harmonics produced by a HVDC converter. The following designs for the active filter concepts are compared with the existing ac-side and dc-side passive filters used at the Dickinson terminal of the CU HVDC transmission line project: the dc-side active filter consisting of a capacitor coupled current injection source to actively ''neutralize'' the 12th, 24th and the 36th harmonics and, the ac-side active filter designed to provide the same fundamental frequency reactive VARs as the existing passive filters. Controlled currents are injected to actively filter the 11th and the 13th harmonic currents. A cost comparison is made between these active filter designs and existing passive filters supplied by the United Power Association (UPA). 22 figs., 11 tabs.

Mohan, N.; Wong, C.

1988-08-01T23:59:59.000Z

440

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

Science Conference Proceedings (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 Baños; Consolación Gil; Antonio Espín; Alfredo Alcayde; Julio Gómez

2010-08-01T23:59:59.000Z

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.


441

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

442

Original article: Selective compensation of voltage harmonics in grid-connected microgrids  

Science Conference Proceedings (OSTI)

In this paper, a novel approach is proposed for selective compensation of main voltage harmonics in a grid-connected microgrid. The aim of compensation is to provide a high voltage quality at the point of common coupling (PCC). PCC voltage quality is ... Keywords: Distributed generator (DG), Grid-connected, Microgrid, Voltage harmonics compensation

Mehdi Savaghebi, Juan C. Vasquez, Alireza Jalilian, Josep M. Guerrero, Tzung-Lin Lee

2013-05-01T23:59:59.000Z

443

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

DOE Green Energy (OSTI)

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

444

Voltage Stability/Security Assessment and On-Line Control: Volumes 1-4  

Science Conference Proceedings (OSTI)

To address growing utility concerns of voltage instability and possible voltage collapse, EPRI has developed a new voltage stability analysis package for large power systems, VSTAB. This off-line planning tool provides information on a utility power system's proximity to and mechanism of voltage instability.

1993-05-01T23:59:59.000Z

445

Impact of MOSFET's performance on its threshold voltage and its influence on design of MOS inverters  

Science Conference Proceedings (OSTI)

The aim of this paper is to research the impact of physical parameters which characterize the MOSFET transistors structure on the threshold voltage values and its influence on critical voltage values which characterize digital circuits that contain the ... Keywords: MOSFET parameters, critical values, doped density, enhancement-type NMOS, impurities, narrow-channel, propagation delay, short-channel, threshold voltage, voltage level

Milaim Zabeli; Nebi Caka; Myzafere Limani; Qamil Kabashi

2008-04-01T23:59:59.000Z

446

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

447

Proceedings: EPRI/NERC forum on voltage stability  

SciTech Connect

Over the past two decades, the interconnected electric systems serving North America have been increasingly subjected to reductions in generation and transmission capacity reserves, increasing complexity of load character, and the need for power transfer over longer distances. As a result, voltage stability limitations are becoming an important factor for utility personnel to consider when designing and operating an electric system. To address this situation, EPRI and NERC cosponsored a forum to exchange information between the various sectors of the utility industry on voltage control technology. The forum covered available tools and practices; utility operating practices, procedures, and experiences; planning and operating studies; and energy management system (EMS) vendor viewpoints. Participants agreed that a continuing coordinated effort involving all industry groups was needed in the voltage stability area. Attendees also identified specific subject areas of importance to help direct future studies. Individual papers are indexed separately.

Maratukulam, D. (ed.) (Kennedy (Thomas), Florissant, MO (United States))

1993-05-01T23:59:59.000Z

448

Variable percentage sampler  

DOE Patents (OSTI)

A remotely operable sampler is provided for obtaining variable percentage samples of nuclear fuel particles and the like for analyses. The sampler has a rotating cup for a sample collection chamber designed so that the effective size of the sample inlet opening to the cup varies with rotational speed. Samples of a desired size are withdrawn from a flowing stream of particles without a deterrent to the flow of remaining particles.

Miller, Jr., William H. (Knoxville, TN)

1976-01-01T23:59:59.000Z

449

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

450

Variable laser attenuator  

SciTech Connect

The disclosure relates to low loss, high power variable attenuators comprng 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.

Foltyn, Stephen R. (Los Alamos, NM)

1988-01-01T23:59:59.000Z

451

Solar-type Variables  

E-Print Network (OSTI)

The rich acoustic oscillation spectrum in solar-type variables make these stars particularly interesting for studying fluid-dynamical aspects of the stellar interior. I present a summary of the properties of solar-like oscillations, how they are excited and damped and discuss some of the recent progress in using asteroseismic diagnostic techniques for analysing low-degree acoustic modes. Also the effects of stellar-cycle variations in low-mass main-sequence stars are addressed.

Houdek, Gunter

2009-01-01T23:59:59.000Z

452

Errors in all variables  

SciTech Connect

We present a thorough derivation of the posterior for the straight line fit employing the hyper-plane prior. For the example of the parabola we enlarge the scope to nonlinear problems, however simplify it to be solved resembling the straight line solution. Finally we come to the problem of determining the exponents of a scaling law, where in logarithmic form the scaling exponents are linear coefficients of logarithmic variables.

Preuss, R.; Dose, V. [Max-Planck-Institut fuer Plasmaphysik, EURATOM Association, D-85748 Garching (Germany)

2005-11-23T23:59:59.000Z

453

High-voltage DC transmission: a power electronics workhorse  

Science Conference Proceedings (OSTI)

Thyristor-based HVDC converter technology is used for highly reliable power transfer across natural or national boundaries or between AC systems designed for different frequencies or incompatible frequency controls. The author discusses the benefits ...

N. G. Hingorani

1996-04-01T23:59:59.000Z

454

Search for Spatial Variability in the Solar Acoustic Spectrum  

E-Print Network (OSTI)

Motivated by the various examples of spatial variability in the power of the acoustic spectrum, we attempted to look for spatial variability in the peak frequency of the spectrum. However, the determination of this peak frequency on a spatial scale of a single pixel (8 arc seconds for the GONG data) is limited by the stochastic variations in the power spectrum presumably caused by the stochastic nature of the excitation process. Averaging over a large number of spectra (100 spectra from a 10 $\\times$ 10 pixels area) produced stabler spectra. The peak frequencies of 130 such locations were found to be distributed with a FWHM of about 130 $\\mu$Hz. A map of the spatial variation of this peak frequency did not show any strong feature with statistically significant deviation from the mean of the distribution. Likewise, the scatter in the peak frequencies masked the detection of magnetic field induced changes in the peak frequency. On a much larger scale, the N latitudes showed a slightly lower value of the peak frequency as compared to the S latitudes, although the difference (25 $\\mu$Hz) is barely larger than the {\\it rms} spread (20 $\\mu$Hz).

P. Venkatakrishnan; Brajesh Kumar; S. C. Tripathy

2001-05-22T23:59:59.000Z

455

SEARCH FOR SPATIAL VARIABILITY IN THE SOLAR ACOUSTIC SPECTRUM  

E-Print Network (OSTI)

Abstract. Motivated by the various examples of spatial variability in the power of the acoustic spectrum, we attempted to look for spatial variability in the peak frequency of the spectrum. However, the determination of this peak frequency on a spatial scale of a single pixel (8 arc seconds for the GONG data) is limited by the stochastic variations in the power spectrum presumably caused by the stochastic nature of the excitation process. Averaging over a large number of spectra (100 spectra from a 10 × 10 pixels area) produced stabler spectra. The peak frequencies of 130 such locations were found to be distributed with a FWHM of about 130 µHz. A map of the spatial variation of this peak frequency did not show any strong feature with statistically significant deviation from the mean of the distribution. Likewise, the scatter in the peak frequencies masked the detection of magnetic field induced changes in the peak frequency. On a much larger scale, the N latitudes showed a slightly lower value of the peak frequency as compared to the S latitudes, although the difference (25 µHz) is barely larger than the rms spread (20 µHz). 1.

P. Venkatakrishnan; Brajesh Kumar; S. C. Tripathy

2001-01-01T23:59:59.000Z

456

Long-Term Wind Power Variability  

DOE Green Energy (OSTI)

The National Renewable Energy Laboratory started collecting wind power data from large commercial wind power plants (WPPs) in southwest Minnesota with dedicated dataloggers and communication links in the spring of 2000. Over the years, additional WPPs in other areas were added to and removed from the data collection effort. The longest data stream of actual wind plant output is more than 10 years. The resulting data have been used to analyze wind power fluctuations, frequency distribution of changes, the effects of spatial diversity, and wind power ancillary services. This report uses the multi-year wind power data to examine long-term wind power variability.

Wan, Y. H.

2012-01-01T23:59:59.000Z

457

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

Science Conference Proceedings (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

458

Cross-Frequency Coupling, Skewness, and Blocking in the Northern Hemisphere Winter Circulation  

Science Conference Proceedings (OSTI)

Variability in daily wintertime [December–February (DJF)] 500-hPa heights on low [L: (6 day)?1] frequencies is examined using 40-yr ECMWF Re-Analysis (ERA-40) data. Leading EOFs of L ...

Kevin J. Rennert; John M. Wallace

2009-11-01T23:59:59.000Z

459

Effects of Distributed Energy Resources on Conservation Voltage Reduction (CVR)  

SciTech Connect

Conservation Voltage Reduction (CVR) is one of the cheapest technologies which can be intelligently leveraged to provide considerable energy savings. The addition of renewables in the form of distributed resources can affect the entire power system, but more importantly, affects the traditional substation control schemes at the distribution level. This paper looks at the effect on energy consumption, peak load reduction, and voltage profile changes due to the addition of distributed generation in a distribution feeder using combinations of volt var control. An IEEE 13-node system is used to simulate the various cases. Energy savings and peak load reduction for different simulation scenarios are compared.

Singh, Ruchi; Tuffner, Francis K.; Fuller, Jason C.; Schneider, Kevin P.

2011-10-10T23:59:59.000Z

460

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

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.


461

Method of determining the open circuit voltage of a battery in a closed circuit  

SciTech Connect

The open circuit voltage of a battery which is connected in a closed circuit is determined without breaking the circuit or causing voltage upsets therein. The closed circuit voltage across the battery and the current flowing through it are determined under normal load and then a fractional change is made in the load and the new current and voltage values determined. The open circuit voltage is then calculated, according to known principles, from the two sets of values.

Brown, William E. (Walnut Creek, CA)

1980-01-01T23:59:59.000Z

462

Optical frequency combs: From frequency metrology to optical ...  

Science Conference Proceedings (OSTI)

... and to dis- tribute the load of the ... measurements of frequency ratios (ie, energy ratios), and ... accuracy or stability versus power consumption, cost, or ...

2004-01-27T23:59:59.000Z

463

Decadal Variability in a Simplified Wind-Driven Ocean Model  

Science Conference Proceedings (OSTI)

The impact of an unsteady wind forcing on oceanic low-frequency variability is conceptually studied using a reduced-gravity shallow-water model. A time-averaged wind forcing and a simple ocean–atmosphere coupling is completed by a stochastic ...

Philip Sura; Frank Lunkeit; Klaus Fraedrich

2000-08-01T23:59:59.000Z

464

Annual Cycle and Variability of the North Brazil Current  

Science Conference Proceedings (OSTI)

Current meter observations from an array of three subsurface moorings located on the Brazil continental slope near 4°N are used to describe the annual cycle and low-frequency variability of the North Brazil Current (NBC). The moored array was ...

W. E. Johns; T. N. Lee; R. C. Beardsley; J. Candela; R. Limeburner; B. Castro

1998-01-01T23:59:59.000Z

465

High frequency transformerless electronics ballast using double inductor-capacitor resonant power conversion for gas discharge lamps  

SciTech Connect

A novel high frequency LCLC double resonant electronic ballast has been developed for gas discharge lamp applications. The ballast consists of a half-bridge inverter which switches at zero voltage crossing and an LCLC resonant circuit which converts a low ac voltage to a high ac voltage. The LCLC resonant circuit has two LC stages. The first LC stage produces a high voltage before the lamp is ignited. The second LC stage limits lamp current with the circuit inductance after the lamp is ignited. In another embodiment a filament power supply is provided for soft start up and for dimming the lamp. The filament power supply is a secondary of the second resonant inductor. 27 figs.

Lai, J.S.

1995-06-20T23:59:59.000Z

466

Jets with Variable R  

E-Print Network (OSTI)

We introduce a new class of jet algorithms designed to return conical jets with a variable Delta R radius. A specific example, in which Delta R scales as 1/pT, proves particularly useful in capturing the kinematic features of a wide variety of hard scattering processes. We implement this Delta R scaling in a sequential recombination algorithm and test it by reconstructing resonance masses and kinematic endpoints. These test cases show 10-20% improvements in signal efficiency compared to fixed Delta R algorithms. We also comment on cuts useful in reducing continuum jet backgrounds.

David Krohn; Jesse Thaler; Lian-Tao Wang

2009-03-02T23:59:59.000Z

467

C17: Voltage Impulse Induced Bistable Magnetization Switching and ...  

Science Conference Proceedings (OSTI)

Non-violate dynamic magnetization switch was also realized by voltage impulse ... Concentric Nanoparticles Embedded in Low Temperature Synthesized TiO2 Films .... F2: Development of the On-Line Mechanical Property Prediction System for ... Sintered Nd-Fe-B Magnets by Transmission Electron Microscopy Analysis.

468

Ultra-compact Marx-type high-voltage generator  

DOE Patents (OSTI)

An ultra-compact Marx-type high-voltage generator includes individual high-performance components that are closely coupled and integrated into an extremely compact assembly. In one embodiment, a repetitively-switched, ultra-compact Marx generator includes low-profile, annular-shaped, high-voltage, ceramic capacitors with contoured edges and coplanar extended electrodes used for primary energy storage; low-profile, low-inductance, high-voltage, pressurized gas switches with compact gas envelopes suitably designed to be integrated with the annular capacitors; feed-forward, high-voltage, ceramic capacitors attached across successive switch-capacitor-switch stages to couple the necessary energy forward to sufficiently overvoltage the spark gap of the next in-line switch; optimally shaped electrodes and insulator surfaces to reduce electric field stresses in the weakest regions where dissimilar materials meet, and to spread the fields more evenly throughout the dielectric materials, allowing them to operate closer to their intrinsic breakdown levels; and uses manufacturing and assembly methods to integrate the capacitors and switches into stages that can be arranged into a low-profile Marx generator.

Goerz, David A. (Brentwood, CA); Wilson, Michael J. (Modesto, CA)

2000-01-01T23:59:59.000Z

469

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

470

Wire-Extrusion Process Disrupted By Voltage Sags  

Science Conference Proceedings (OSTI)

This PQTN Case Study investigates voltage sags originating from a utility distribution system at a wire-extrusion plant near Cleveland, Ohio that were causing a wire-drawing process to malfunction, resulting in broken tungsten wire and hours of time spent restarting the manufacturing process.

2003-12-31T23:59:59.000Z

471

Smart Solar Home System with Safety Device Low Voltage Alert  

Science Conference Proceedings (OSTI)

For many reasons Bangladeshi people are now using renewable energy. So, solar energy is the best renewable energy till now, in respect of Bangladesh. So using of solar system is common nowadays. Bangladesh Government has taken some steps to make solar ... Keywords: Smart Solar Home System (SSHS), Rooftop, Safety Device, Low voltage alert

Tawheed Hasan; Md. Faysal Nayan; Md. Asif Iqbal; Monzurul Islam

2012-03-01T23:59:59.000Z

472

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

473

Design of Low Voltage Low Power Operational Amplifier  

Science Conference Proceedings (OSTI)

With the demand of low power applications, running circuits with reduced supply voltage can be of great advantage. Integrated circuit designers start to face a power wall as the most difficult constraints in new technology and circuit development are ... Keywords: Op Amp, CMOS, LVLP

Manju Sandhu; Manju Bala

2012-01-01T23:59:59.000Z

474

High voltage bipolar-CMOS structure using porous silicon  

DOE Patents (OSTI)

A method for integrating a silicon-on-insulator device and a bulk bipolar device on a semiconductor body. The invention simultaneously forms the two regions for the silicon-on-insulator device and the bipolar device. The invention enables a high voltage CMOS power device to be located on the same chip as a bipolar logic device enabling smart power devices.

Guilinger, T.R.; Kelly, M.J.; Tsao, S.S.

1990-01-01T23:59:59.000Z

475

Analysis on DFIG Wind Power System Low-Voltage Ridethrough  

Science Conference Proceedings (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

476

Power and Voltage Smooth Control of Doubly Fed Induction Generator  

Science Conference Proceedings (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

477

Low-voltage cathodoluminescence of europium-activated yttrium orthovanadate  

Science Conference Proceedings (OSTI)

Emissive flat panel display systems operating in full color demand higher performance at low voltages (ca. 501000 V) from cathodoluminescent (CL) phosphors than cathode ray tubes require. Hydrothermal synthesis has been suggested as a route to phosphors with improved efficiencies, lower voltage thresholds, and increased saturation power. This hypothesis was tested in europium-doped yttrium orthovanadate (YVO{sub 4}:Eu), an efficient, red emitting CL phosphor. The CL efficiency of YVO{sub 4}:Eu crystallized from aqueous solution at 200{degrees}C is relatively low until it is annealed. The distribution of particle sizes in the low-temperature phosphor is similar to that in material made via a solid-state route, but crystallites remain much smaller (ca. 400 {Angstrom}) until they are annealed. These observations, along with the anomalously strong dependence of CL intensity on europium concentration, support a model in which efficiency principally depends on crystallite size. CL efficiency of both solid state and hydrothermal YVO{sub 4}:Eu increases with voltage at constant power. Surface-bound electrons are likely the dominant influence on efficiency at voltages near threshold. Saturation power is independent of synthetic route. It is apparent that the CL properties of hydrothermally synthesized YVO{sub 4}:Eu are essentially the same as those of YVO{sub 4}:Eu produced via conventional, high-temperature routes.

Phillips, M.L.F.

1995-03-01T23:59:59.000Z

478

High Voltage Laboratory Testing of Femtosecond Laser Lightning Diversion  

Science Conference Proceedings (OSTI)

Lightning strikes cost the electric power industry an estimated 1 billion dollars annually in damage and lost revenue. One possible way of protecting critical and susceptible facilities from lightning strikes is to use lasers to trigger and divert lightning along a predetermined path. This report describes laboratory research on the use of ultrashort UV pulses and near IR pulses to trigger high voltage discharge.

1998-12-09T23:59:59.000Z

479

Voltage stability/security assessment and on-line control  

SciTech Connect

Project RP3040-1 was initiated in 1989, and concluded with the release of the Voltage Stability analysis program, VSTAB, in 1992. VSTAB is a production grade program for voltage stability assessment of large complex power systems. During the course of the RP3040-1, much effort was spent in developing a clear understanding of voltage stability and in defining the special modeling and analytical techniques required to accurately capture the phenomenon through simulation. The result was the development of new steady state methods which can complement the dynamic simulation methods currently available with EPRI's Extended Transient/Midterm Stability Program (ETMSP). VSTAB uses an enhanced powerflow combined with a specially developed modal analysis algorithm to provide information regarding both the proximity to, and mechanism of, voltage instability. The program is fast, easy to use, and comprehensive in both modeling and analysis features. This Programmer's Manual documents the structure and code details of VSTAB. It is intended as a reference document for those required to maintain or enhance the VSTAB program. For details on analytical techniques used in the program, readers are directed to the VSTAB Application Guide and Final Report for project RP3040-1.

Morison, G.K.; Gao, B.; Hamadanizadeh, H. (Ontario Hydro, Toronto, ON (Canada))

1993-04-01T23:59:59.000Z

480

Hierarchical Control Scheme for Voltage Unbalance Compensation in Islanded Microgrids  

E-Print Network (OSTI)

Hierarchical Control Scheme for Voltage Unbalance Compensation in Islanded Microgrids Mehdi@et.aau.dk Abstract-- The concept of microgrid hierarchical control is presented, recently. In this paper, a hierarchical scheme which includes primary and secondary control levels is proposed for islanded microgrids

Vasquez, Juan Carlos

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481

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

482

Effective switching frequency multiplier inverter  

SciTech Connect

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

483

Frequency Control Performance Measurement and Requirements  

E-Print Network (OSTI)

power systems operations could significantly influence primary frequency control.power system operations could not significantly influence primary frequency control.power system operations. Determination of frequency control

Illian, Howard F.

2011-01-01T23:59:59.000Z

484

Infrastructure Failure - Types and Frequency  

U.S. Energy Information Administration (EIA)

Infrastructure Failure - Types and Frequency. Small events that have no impact on supplies Events that require supply/demand responses Events that result in a ...

485

Time and Frequency Division Homepage  

Science Conference Proceedings (OSTI)

... Controlled ClocksTelephone TimeDivision HistoryFrequently Asked Questions (FAQ)Time and Frequency from A to Z: An illustrated glossaryA Walk ...

2013-12-27T23:59:59.000Z

486

Dynamic frequency allocation in fractional frequency reused OFDMA networks  

Science Conference Proceedings (OSTI)

This paper proposes a dynamic fractional frequency reused cell architecture that simplifies the problem of subcarrier allocation with frequency reuse in multicell OFDMA networks. The architecture divides the cell surface into two overlapping geographical ... Keywords: 3G, cellular networks, cross-layer adaptation, data networks, mobile communication systems, opportunistic scheduling, wireless communication

Syed Hussain Ali; Victor C. M. Leung

2009-08-01T23:59:59.000Z

487

Solar Irradiance Variability  

E-Print Network (OSTI)

The Sun has long been considered a constant star, to the extent that its total irradiance was termed the solar constant. It required radiometers in space to detect the small variations in solar irradiance on timescales of the solar rotation and the solar cycle. A part of the difficulty is that there are no other constant natural daytime sources to which the Sun's brightness can be compared. The discovery of solar irradiance variability rekindled a long-running discussion on how strongly the Sun affects our climate. A non-negligible influence is suggested by correlation studies between solar variability and climate indicators. The mechanism for solar irradiance variations that fits the observations best is that magnetic features at the solar surface, i.e. sunspots, faculae and the magnetic network, are responsible for almost all variations (although on short timescales convection and p-mode oscillations also contribute). In spite of significant progress important questions are still open. Thus there is a debat...

Solanki, Sami K

2012-01-01T23:59:59.000Z

488

Joint Spatiotemporal Variability of Global Sea Surface Temperatures and Global Palmer Drought Severity Index Values  

Science Conference Proceedings (OSTI)

Dominant modes of individual and joint variability in global sea surface temperatures (SST) and global Palmer drought severity index (PDSI) values for the twentieth century are identified through a multivariate frequency domain singular value ...

Somkiat Apipattanavis; Gregory J. McCabe; Balaji Rajagopalan; Subhrendu Gangopadhyay

2009-12-01T23:59:59.000Z

489

Monitoring North Pacific Heat Content Variability: An Indicator of Fish Quantity?  

Science Conference Proceedings (OSTI)

Fields of modeled sea surface heights and temperatures are used to develop an algorithm to monitor the low-frequency heat content variability of the North Pacific's midlatitudes associated with regime shifts in the circulation patterns of the ...

R. Tokmakian

2003-11-01T23:59:59.000Z

490

Subseasonal and Interannual Temperature Variability in Relation to Extreme Temperature Occurrence over East Asia  

Science Conference Proceedings (OSTI)

This study investigates interannual variability in the frequency of occurrence of daily surface air temperature (SAT) extremes over East Asia in summer and winter between 1979 and 2009. We examine the dominant seasonal SAT patterns, as obtained ...

Hiroyuki Ito; Nathaniel C. Johnson; Shang-Ping Xie

491

Interdecadal Trend and ENSO-Related Interannual Variability in Southern Hemisphere Blocking  

Science Conference Proceedings (OSTI)

The interdecadal trend and ENSO-related interannual variability in the frequency and intensity of atmospheric blocking in the Southern Hemisphere are analyzed by a statistical model that takes account of serial correlation in the datasets. ...

Li Dong; Timothy J. Vogelsang; Stephen J. Colucci

2008-06-01T23:59:59.000Z

492

Secular Changes of Annual and Interannual Variability in the Tropics during the Past Century  

Science Conference Proceedings (OSTI)

Wavelet transforms, which can unfold signals in both time and frequency domains, are used to analyze the Comprehensive Ocean and Atmospheric Data Sets for the period 1870–1988. The focus is on secular changes in the interannual variability and ...

Daifang Gu; S. G. H. Philander

1995-04-01T23:59:59.000Z

493

Aspects of the Tidal Variability Observed on the Southern California Continental Shelf  

Science Conference Proceedings (OSTI)

Observations of the current and temperature field from the southern California continental shelf are analyzed in a frequency band (0.6–6 cpd) dominated by tidal fluctuations. The seasonal variability of the temperature and horizontal velocity ...

A. Bratkovich

1985-03-01T23:59:59.000Z

494

Satellite-Derived Interannual Variability of West African Rainfall during 1983?88  

Science Conference Proceedings (OSTI)

Two satellite algorithms for rain estimation are used to study the interannual variability of West African rainfall during contrasting years of the period 1983?88. The first algorithm uses a frequency of occurrence index quantifying the number of ...

Mamoudou B. Ba; Robert Frouin; Sharon E. Nicholson

1995-0