Detection method of current sensor faults in the e-drive system by using the voltage command error

• US 9,372,234 B2
• Filed: 08/27/2013
• Issued: 06/21/2016
• Est. Priority Date: 08/27/2013
• Status: Active Grant

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Wang, Chang-jiang, Degner, Michael, Isayeva, Rimma, Xu, Liwen, Luedtke, Daniel R.
• Primary Examiner(s): NGUYEN, VINH P
• Application Number:
  US14/011,720
• Publication Number:
  US 20150061708A1
• Time in Patent Office: 1,029 Days
• US Class Current: 1/1
• CPC Class Codes: G01R 31/3191 Calibration
• CPC Class Codes: H02P 29/024 Detecting a fault condition, e.g. short circuit, locked rotor, open circuit or loss of load
• CPC Class Codes: H02P 29/0241 the fault being an overvoltage

Abstract

Systems, apparatus, and methods detect a current sensor error in an FOC electric machine system. A voltage command is monitored to detect the presence of an ac component that indicates that an error has occurred at a current sensor. For example, a sensor fault detection module can be configured to determine the deviation between an actual voltage command and an ideal voltage command to provide a complex deviation vector. By transforming the deviation vector to a reference frame rotating at the fundamental frequency of the command voltage, a dc component of the positive and negative sequences can be filtered, and their amplitudes determined. Error detection can be based on the total amplitude of the fundamental component, determined by positive and negative component amplitudes. Sensor error detection enables an FOC system to operate with two current sensors, rather than three, and provides a dedicated fault diagnostic for a current sensor.

Claims

1. A system, comprising:

an electric machine (EM);

an energy conversion module (ECM) configured to provide energy to said EM;

a sensor configured to sense a phase current between said ECM and said EM and provide feedback current;

a controller configured to provide a voltage command configured to cause production of a desired torque by said EM, said voltage command dependent on said feedback current provided by said sensor; and

a sensor fault detection module (SFDM) configured to isolate and use an ac component of said voltage command to detect an error at said sensor.

2. The system of claim 1, wherein said ac component comprises a fundamental frequency component of said voltage command.

3. The system of claim 2, wherein said SFDM is configured to determine the negative sequence of said fundamental frequency component.

4. The system of claim 1, wherein said SFDM is configured to determine a deviation between said voltage command provided by said controller and an ideal voltage command, and use said deviation to detect said error.

5. The system of claim 1, wherein said ac component comprises a harmonic component of said actual voltage command.

6. A sensor fault detection module (SFDM), comprising:

an ac component monitoring module (ACMM) having a voltage mapping module (VMM) configured to provide an ideal voltage command configured to effect a desired electric machine (EM) torque output, a deviation determination module (DDM) configured to determine a deviation between said ideal voltage command and an actual voltage command provided for said EM, said actual voltage command dependent on feedback current provided by a sensor configured to sense phase current for said EM, and an ac component magnitude module (MAGM) configured to determine the magnitude of an ac component of said deviation between said ideal and actual voltage commands; and

an error determination module (EDM) configured to use said magnitude to determine whether an error is present at said sensor.

7. The SFDM of claim 6, wherein said DDM is configured to isolate a fundamental frequency component of said actual voltage command.

8. The SFDM of claim 7, wherein said DDM is configured to determine the negative sequence of said fundamental frequency component.

9. The SFDM of claim 6, wherein said DDM is configured to isolate a harmonic component of said actual voltage command.