Electric motor driver with current sensor error correction

Patent metadata

Field	Value
Publication number	US-2016276969-A1
Application number	US-201514664448-A
Country	US
Kind code	A1
Filing date	Mar 20, 2015
Priority date	Mar 20, 2015
Publication date	Sep 22, 2016
Grant date	—

Abstract

A system configured to operate an electric motor and correct for current measurement errors present in current sensors used by the system includes a plurality of voltage drivers, a plurality of current sensors, and a controller. Each of the plurality of voltage drivers is electrically coupled to each phase of a motor. Each of the plurality of current sensors is each configured to measure current in each phase of the motor. The controller is configured to sample a current-signal from each current sensor, and determine a baseline-offset error of each current sensor based on a plurality of samples of the current-signal from each current sensor while the motor is rotating.

First claim

We claim:

1 . A system configured to operate an electric motor and correct for current measurement errors present in current sensors used by the system, said system comprising:
a plurality of voltage drivers electrically coupled to each phase of a motor; a plurality of current sensors, each current sensor configured to measure current in each phase of the motor; a controller configured to sample a current-signal from each current sensor, and determine a baseline-offset error of each current sensor based on a plurality of samples of the current-signal from each current sensor while the motor is rotating.

2 . The system in accordance with claim 1 , wherein the plurality of samples are taken while all phases of the motor are electrically shorted together by the plurality of voltage drivers.

3 . The system in accordance with claim 1 , wherein the plurality of samples are taken over an integer number of electrical rotations of the motor.

4 . The system in accordance with claim 1 , wherein the plurality of samples are taken over an integer number of physical rotations of the motor.

5 . The system in accordance with claim 1 , wherein the system includes a temperature sensor positioned to determine an operating-temperature of the plurality of current sensors.

6 . The system in accordance with claim 5 , wherein the controller is further configured to determine a temperature-offset error of each current sensor based on the operating-temperature.

7 . The system in accordance with claim 1 , wherein the controller is further configured to determine a gain error of each current sensor based on a composite-current value.

8 . The system in accordance with claim 7 , wherein the composite-current value is based on one of a maximum-current value, a root-mean-square current value, and a frequency-transformation value.

9 . The system in accordance with claim 7 , wherein the system includes a temperature sensor positioned to determine an operating-temperature of the plurality of current sensors.

10 . A method to operate an electric motor and correct for current measurement errors present in current sensors used in phases of the motor, said method comprising:
providing a plurality of voltage drivers electrically coupled to each phase of a motor; providing a plurality of current sensors, each current sensor configured to measure current in each phase of the motor; sampling a current-signal from each current sensor; and determining a baseline-offset error of each current sensor based on a plurality of samples of the current-signal from each current sensor while the motor is rotating.

Assignees

• Delphi Tech Inc

Inventors

• Krefta Ronald J

Classifications

• H02P21/0035 Primary

  Electricity · mapped topic

• H02P29/0088

  Electricity · mapped topic

• H02P27/06

  using DC to AC converters or inverters (H02P27/05 takes precedence) · CPC title

• H02P29/032 Primary

  Preventing damage to the motor, e.g. setting individual current limits for different drive conditions · CPC title

• G01R35/005

  Calibrating; Standards or reference devices, e.g. voltage or resistance standards, "golden" references (G01R33/0035, G01R35/002 take precedence) · CPC title