Feedback parameter estimation for electric machines

• US 7,199,549 B2
• Filed: 12/11/2001
• Issued: 04/03/2007
• Est. Priority Date: 08/17/2001
• Status: Expired due to Fees

• Current Assignee: GM Global Technology Operations Incorporated (General Motors Company), Steering Solutions IP Holding Corporation (Nexteer Automotive Group Ltd.)
• Original Assignee: Delphi Technologies, Inc. (BorgWarner Incorporated)
• Inventors: Collier-Hallman, Steven J., Chandy, Ashok, Kleinau, Julie A., Patankar, Ravindra P.
• Primary Examiner(s): Fletcher; Marlon
• Application Number:
  US10/013,932
• Publication Number:
  US 20030071594A1
• Time in Patent Office: 1,939 Days
• Field of Search: 318705-708, 318781-791, 318798-803, 318/567, 388/934, 361/161, 361/165
• US Class Current: 318/798
• CPC Class Codes: B60L 15/025 using field orientation; Vector control; Direct Torque Control [DTC]
• CPC Class Codes: B60L 2260/56 Temperature prediction, e.g. for pre-cooling
• CPC Class Codes: B60L 50/16 with provision for separate direct mechanical propulsion
• CPC Class Codes: B60L 50/51 characterised by AC-motors
• CPC Class Codes: B62D 5/0496 by using a temperature sensor
• CPC Class Codes: G01K 7/21 for modifying the output characteristic, e.g. linearising
• CPC Class Codes: G05B 13/042 in which a parameter or coefficient is automatically adjusted to optimise the performance
• CPC Class Codes: G05B 17/02 electric
• CPC Class Codes: H02P 23/14 Estimation or adaptation of motor parameters, e.g. rotor time constant, flux, speed, current or voltage
• CPC Class Codes: H02P 29/64 Controlling or determining the temperature of the winding
• CPC Class Codes: H02P 29/662 the rotor having permanent magnets H02P29/67 takes precedence
• CPC Class Codes: H02P 29/68 based on the temperature of a drive component or a semiconductor component
• CPC Class Codes: Y02T 10/64 Electric machine technologies in electromobility
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries
• CPC Class Codes: Y02T 10/7072 Electromobility specific charging systems or methods for batteries, ultracapacitors, supercapacitors or double-layer capacitors

Abstract

A method and system for estimating a parameter of an electric machine, including a controller and a switching device, the controller executes a parameter estimation process, which is responsive to at least one of: a current value and a torque command and the resultant of the parameter estimation process representing an estimated parameter of the electric machine. The parameter estimation includes a method for estimating a temperature of the electric machine comprising: a temperature sensor operatively connected to and transmitting a temperature signal corresponding to a measured temperature to a controller, which executes a temperature estimation process responsive to a temperature signal from a temperature sensor.

Claims

1. A system for estimating a parameter of an electric machine, comprising:

a controller operatively connected to a switching device, said switching device operatively connected between said electric machine and a power source, said switching device being coupled to said controller;

a current sensing device operatively connected to said electric machine and said controller for providing a torque signal indicative of a measured torque for said electric machine; and

said controller executing a parameter estimation process, said controller being receptive to said torque signal and a torque command indicative of a desired torque for said electric machine, said parameter estimation process includes,

determining an estimated torque in response to said torque signal,

determining a torque error by comparing said torque command signal with said estimated torque in a time coherent manner, and

integrating said torque error to generate a parameter estimate, said parameter estimate representing a parameter of said electric machine, said integrating said torque error being disabled when a rate of change of said torque command signal exceeds a threshold.

2. The system of claim 1 wherein said electric machine comprises an electric motor.

3. The system of claim 1 wherein said parameter comprises at least one of a resistance, an inductance, and a motor constant.

4. The system of claim 1 wherein said parameter estimation process compensates for build and life variations in said parameter of said electric machine.

5. The system of claim 1 further including:

a velocity sensor disposed to measure a velocity of said electric machine and transmitting a velocity signal to said controller, said parameter estimation process determining said estimated torque in response to said torque value and said velocity signal.

6. The system of claim 5 wherein said parameter estimation process determines said estimated torque in response to said torque value, said velocity signal, and a prior torque command.

7. The system of claim 1 wherein said integrating said torque error comprises one of an error accumulator and a conditional integrator.

8. The system of claim 1 wherein said error accumulator is initialized to a nominal value of said parameter.

9. The system of claim 1 wherein said controller receives an estimate good flag.

10. The system of claim 9 wherein said estimate good flag is indicative of a validity of said estimated torque.

11. The system of claim 9 wherein said said integrating said torque error is responsive to said estimate good flag.

12. The system of claim 11 wherein said integrating said torque error is disabled when said estimate good flag indicates an invalid estimated torque.

13. The system of claim 1 wherein said controller receives a rate flag.

14. The system of claim 13 wherein said rate flag is indicative of said rate of change of said torque command signal.

15. The system of claim 1 wherein said threshold is two amperes over a 2 millisecond duration.

16. A method for estimating a parameter of an electric machine, comprising:

receiving a torque value indicative of a measured torque for said electric machine and a torque command indicative of a desired torque for said electric machine; and

executing a parameter estimation process, said parameter estimation process includes,

determining an estimated torque in response to said torque signal,

determining a torque error by comparing said torque command signal with said estimated torque in a time coherent manner, and

integrating said torque error to generate a parameter estimate, said parameter estimate representing a parameter of said electric machine, said integrating said torque error being disabled when a rate of change of said torque command signal exceeds a threshold.

17. The method of claim 16 wherein said electric machine comprises an electric motor.

18. The method of claim 16 wherein said parameter comprises at least one of a resistance, an inductance, and a motor constant.

19. The method of claim 16 wherein said parameter estimation process compensates for build and life variations in said parameter of said electric machine.

20. The method of claim 16 further including obtaining a velocity signal responsive to a velocity of said electric machine, said parameter estimation process determining said estimated torque in response to said torque value and said velocity signal.

21. The method of claim 20 wherein said parameter estimation process determines said estimated torque in response to said torque value, said velocity signal, and a prior torque command.

22. The method of claim 16 wherein said integrating said torque error comprises one of an error accumulator and a conditional integrator.

23. The method of claim 16 wherein said error accumulator is initialized to a nominal value of said parameter.

24. The method of claim 16 further comprising receiving an estimate good flag.

25. The method of claim 24 wherein said estimate good flag is indicative of a validity of said estimated torque.

26. The method of claim 24 wherein said integrating said torque error is responsive to said estimate good flag.

27. The method of claim 26 wherein said integrating said torque error is disabled when said estimate good flag indicates an invalid estimated torque.

28. The method of claim 16 further comprising receiving a rate flag.

29. The method of claim 28 wherein said rate flag is indicative of said rate of change of said torque command signal.

30. The method of claim 16 wherein said selected threshold is two amperes over a 2 millisecond duration.

31. A storage medium encoded with computer program code,

said code comprising instructions for causing a controller to implement a method for estimating a parameter of an electric machine the method comprising:

receiving a torque value indicative of a measured torque for said electric machine and a torque command indicative of a desired torque for said electric machine; and

executing a parameter estimation process, said parameter estimation process includes.

determining an estimated torque in response to said torque signal,

determining a torque error by comparing said torque command signal with said estimated torque in a time coherent manner, and

integrating said torque error to generate a parameter estimate, said parameter estimate representing a parameter of said electric machine, said integrating said torque error being disabled when a rate of change of said torque command signal exceeds a threshold.

32. The storage medium of claim 31 wherein said parameter comprises at least one of a resistance, an inductance, and a motor constant.

33. The storage medium of claim 31 wherein said parameter estimation process compensates for build and life variations in said parameter of said electric machine.

34. The storage medium of claim 31 further including obtaining a velocity signal responsive to a velocity of said electric machine, said parameter estimation process determining said estimated torque in response to said torque value and said velocity signal.

35. The storage medium of claim 34 wherein said parameter estimation process determines said estimated torque in response to said torque value, said velocity signal, and a prior torque command.

36. The storage medium of claim 31 wherein said integrating said torque error comprises one of an error accumulator and a conditional integrator.

37. The storage medium of claim 31 wherein said error accumulator is initialized to a nominal value of said parameter.

38. The storage medium of claim 31 further comprising instructions for causing said controller to implement a method further comprising receiving an estimate good flag.

39. The storage medium of claim 38 wherein said estimate good flag is indicative of a validity of said estimated torque.

40. The storage medium of claim 38 further comprising instructions for causing said controller to implement a method further comprising receiving a rate flag.

41. The storage medium of claim 40 wherein said rate flag is indicative of said rate of change of said torque command signal.

42. A computer data signal embodied in a carrier wave, the computer data signal comprising:

code configured to cause a controller to implement a method for estimating a parameter of an electric machine, the method comprising;

receiving a torque value indicative of a measured torque for said electric machine and a torque command indicative of a desired torque for said electric machine; and

executing a parameter estimation process, said parameter estimation process includes,

determining an estimated torque in response to said torque signal,

determining a torque error by comparing said torque command signal with said estimated torque in a time coherent manner, and

integrating said torque error to generate a parameter estimate, said parameter estimate representing a parameter of said electric machine, said integrating said torque error being disabled when a rate of change of said torque command signal exceeds a threshold.

43. The computer data signal of claim 42 wherein said parameter comprises at least one of a resistance, an inductance, and a motor constant.

44. The computer data signal of claim 42 wherein said parameter estimation process compensates for build and life variations in said parameter of said electric machine.

45. The computer data signal of claim 42 further including obtaining a velocity signal responsive to a velocity of said electric machine, said parameter estimation process determining said estimated torque in response to said torque value and said velocity signal.

46. The computer data signal of claim 45 wherein said parameter estimation process determines said estimated torque in response to said torque value, said velocity signal, and a prior torque command.

47. The computer data signal of claim 42 wherein said integrating said torque error comprises one of an error accumulator and a conditional integrator.

48. The computer data signal of claim 42 wherein said error accumulator is initialized to a nominal value of said parameter.

49. The computer data signal of claim 42 further comprising instructions for causing said controller to implement a method further comprising receiving an estimate good flag.

50. The computer data signal of claim 49 wherein said estimate good flag is indicative of a validity of said estimated torque.

51. The computer data signal of claim 42 further comprising instructions for causing said controller to implement a method further comprising receiving a rate flag.

52. The computer data signal of claim 51 wherein said rate flag is indicative of said rate of change of said torque command signal.