Reliable current sensing for inverter-controlled electric machine
a technology of inverter-controlled electric machines and current sensing, which is applied in the direction of power supply testing, instruments, and measurement using digital techniques, etc., and can solve problems such as calibration/consistency problems
Active Publication Date: 2016-09-08
FORD GLOBAL TECH LLC
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Benefits of technology
The invention is an electric drive for an electric vehicle that uses a multi-phase electric machine. It includes an inverter bridge with inverter switches arranged in multiple phase legs. The inverter controller controls the switches and sends current signals to the motor through first and second phase conductors. The current signals are generated by current sensors and then conditioned by multi-channel op amp devices. The conditioned current signals are then received by the inverter controller, ensuring valid signals are received for each phase conductor. The technical effect of this invention is to improve the accuracy and reliability of the electric drive for electric vehicles.
Problems solved by technology
The use of redundant current sensors can increase reliability, but use of multiple sensors for each phase has introduced calibration / consistency issues when using redundant sensors to take multiple measurements of one phase current.
Method used
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Embodiment Construction
[0018]Referring now to FIG. 1, a vehicle 10 is shown as a hybrid electric vehicle with an electric drive system 18. Although a powersplit hybrid layout is shown, the present invention is also applicable to any type of electric vehicle (e.g., HEV, PHEV, or a fully electric vehicle). An internal combustion engine 11 and a battery pack 12 supply energy for propelling vehicle 10. Battery 12 drives a motor 13 with an output coupled to transmission gears 14 for driving vehicle wheels 15. A mechanical output of engine 11 is coupled to gears 14 via a splitting device 16 for providing an engine-driven mode of the powertrain. Splitting device 16 also couples gears 14 to a generator 17 so that during regenerative braking, available mechanical power from wheels 15 can be used to rotate generator 17, with recovered energy being used to charge battery 12 as known in the art. Thus, the electric machines (i.e., motor 13 and generator 17) are each coupled to wheels 15 for bidirectionally converting ...
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Phase currents of an inverter-driven electric machine are measured by mounting phase conductors of each respective phase current into a central passage of a respective flux core. A plurality of current sensors are mounted into a gap of each respective flux core to generate a respective plurality of current signals for each phase current. The Hall-effect devices are connected to a plurality of multi-channel op amp devices for conditioning the current signals such that each set of Hall-effect devices is connected to a different one of the op amp devices and such that each op amp device receives one current signal corresponding to each phase current. Thus, a valid conditioned current signal corresponding to each phase conductor is generated by the op amp devices unless there are multiple simultaneous failures of the Hall-effect devices and the op amp devices.
Description
CROSS REFERENCE TO RELATED APPLICATIONS[0001]Not Applicable.STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH[0002]Not Applicable.BACKGROUND OF THE INVENTION[0003]The present invention relates in general to current sensing for controlling inverter-driven electric machines, and, more specifically, to increased fault tolerance for current sensing in connection with electric vehicle drives.[0004]Electric vehicles, such as hybrid electric vehicles (HEVs) and plug-in hybrid electric vehicles (PHEVs), use inverter-driven electric machines to provide traction torque and regenerative braking torque. A typical electric drive system includes a DC power source (such as a battery pack or a fuel cell) coupled by contactor switches to a variable voltage converter (VVC) to regulate a main bus voltage across a main linking capacitor. A first inverter is connected between the main bus and a traction motor to propel the vehicle. A second inverter may be connected between the main bus and a generator t...
Claims
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Patent Timeline
Login to View More IPC IPC(8): H02P6/00B60L11/18H02K11/00
CPCH02P6/002B60L11/1803H02K11/0057G01R19/25B60L50/51G01R15/202G01R31/343G01R31/42H02P27/06Y02T10/70H02P27/08H02K11/27H02K11/33
InventorGARCHA, JASWANT S.
OwnerFORD GLOBAL TECH LLC