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Title: Current sensor

Abstract

A current sensor is described that uses a plurality of magnetic field sensors positioned around a current carrying conductor. The sensor can be hinged to allow clamping to a conductor. The current sensor provides high measurement accuracy for both DC and AC currents, and is substantially immune to the effects of temperature, conductor position, nearby current carrying conductors and aging.

Inventors:
; ;
Publication Date:
Research Org.:
FieldMetrics, Inc., Seminole, FL (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1176076
Patent Number(s):
7,164,263
Application Number:
10/905,509
Assignee:
FieldMetrics, Inc. (Seminole, FL) OSTI
DOE Contract Number:
FG03-01ER83228
Resource Type:
Patent
Country of Publication:
United States
Language:
English
Subject:
47 OTHER INSTRUMENTATION

Citation Formats

Yakymyshyn, Christopher Paul, Brubaker, Michael Allen, and Yakymyshyn, Pamela Jane. Current sensor. United States: N. p., 2007. Web.
Yakymyshyn, Christopher Paul, Brubaker, Michael Allen, & Yakymyshyn, Pamela Jane. Current sensor. United States.
Yakymyshyn, Christopher Paul, Brubaker, Michael Allen, and Yakymyshyn, Pamela Jane. Tue . "Current sensor". United States. doi:. https://www.osti.gov/servlets/purl/1176076.
@article{osti_1176076,
title = {Current sensor},
author = {Yakymyshyn, Christopher Paul and Brubaker, Michael Allen and Yakymyshyn, Pamela Jane},
abstractNote = {A current sensor is described that uses a plurality of magnetic field sensors positioned around a current carrying conductor. The sensor can be hinged to allow clamping to a conductor. The current sensor provides high measurement accuracy for both DC and AC currents, and is substantially immune to the effects of temperature, conductor position, nearby current carrying conductors and aging.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Tue Jan 16 00:00:00 EST 2007},
month = {Tue Jan 16 00:00:00 EST 2007}
}

Patent:

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  • A method is described to provide temperature compensation and self-calibration of a current sensor based on a plurality of magnetic field sensors positioned around a current carrying conductor. A reference electrical current carried by a conductor positioned within the sensing window of the current sensor is used to correct variations in the output signal due to temperature variations and aging.
  • A system for feedback control of air/fuel ratio in an ic engine, utilizing an oxygen-sensitive device which is provided with a heater and disposed in exhaust gas to provide a feedback signal. This device has a porous solid electrolyte layer with an outer electrode layer on one side and an inner electrode on the other side facing a substrate. There is a circuit to supply a heating current to the heater and also force a dc current to flow in the solid electrolyte layer to cause migration of oxygen ions therethrough toward the inner electrode to thereby establish a referencemore » oxygen partial pressure on the inner side of the solid electrolyte layer. This circuit is provided with current intensity regulation means to temporarily decrease the intensity of the current flowing in the solid electrolyte layer by a predetermined value while the oxygen-sensitive device is not sufficiently heated to thereby preclude undesirable rise of the basic level of the output voltage of the oxygen-sensitive device by the effect of an increased internal resistance of the not sufficiently heated element.« less
  • A system for feedback control of air/fuel ratio in an IC engine is disclosed, utilizing a recently developed oxygen-sensitive device which is provided with a heater and disposed in exhaust gas to provide a feedback signal. This device has a porous solid electrolyte layer with a measurement electrode layer on one side and a reference electrode on the other side facing a substrate. There is a circuit to supply a heating current to the heater and force a dc current to flow in the solid electrolyte layer to cause migration of oxygen ions through the solid electrolyte toward the referencemore » electrode to thereby establish a reference oxygen partial pressure on the reference side of the solid electrolyte layer. To prevent lowering of this oxygen partial pressure while the engine is operated under a high-load condition and the feedback control is discontinued to feed the engine with a fuel-enriched mixture, the control system includes operating condition sensor means and switching means to interrupt the supply of the current to the heater in response to a command signal from the sensor means and, optionally, current regulating means to increase the intensity of current flowing in the solid electrolyte also in response to the command signal.« less
  • An air/fuel ratio control system is disclosed including an oxygen sensor disposed in the exhaust gas to provide a feedback signal. The oxygen sensor is of the solid electrolyte concentration cell type having a heater and is operated with supply of a DC current to the concentration cell to maintain a reference oxygen partial pressure therein. A fuel feed control circuit in this system shifts its closed-looped control function to open-loop aiming at a lower air/fuel ratio if the output of the oxygen sensor continues to indicate that actual air/fuel ratio remains on one side of the intended air/fuel ratiomore » due to breaking of the heater. To prevent the engine from stalling or operating unstably due to excessive increase in the air/fuel ratio before the shift to open-loop control, the system includes means for detecting breaking of the heater and immediately interrupting the current supply to the concentration cell in the oxygen sensor thereby forcing the sensor to put out an output which is indicative of a very high air/fuel ratio and, hence, causes the control circuit to lower the air/fuel ratio before the interruption of the closed-loop control.« less
  • Mixture ratio control for internal combustion engines supplies a constant current into an exhaust gas sensor to develop a voltage of a substantial magnitude in proportion to the initial high value of the gas sensor internal impedance during low temperature conditions. The voltage so developed decreases as a function of time corresponding to the decrease of the internal impedance with temperature. A voltage detector is provided to trigger the control system to operate in a closed loop mode when the gas sensor voltage is reduced to a level below a first threshold level. Responsive to the output of the voltagemore » detector the supplied current is momentarily interrupted to allow the gas sensor voltage to drop rapidly to a level which is higher or lower than a second threshold level depending on the concentration of the sensed gas in the exhaust system. A second detector senses this voltage drop relative to the second threshold to determine whether the gas sensor output represents rich or lean condition. The reference point of the closed loop is raised or lowered in response to the output of the second detector and further decreased as a function of time such that the reference point lies within the range between maximum and minimum peak values of the gas sensor output signal.« less