Feedback parameter estimation for electric machines

• US 20030071594A1
• Filed: 12/11/2001
• Published: 04/17/2003
• Est. Priority Date: 08/17/2001
• Status: Active Grant

• Current Assignee: GM Global Technology Operations Incorporated (Motors Liquidation Co. GUC Trust), Steering Solutions IP Holding Corporation (Nexteer Automotive Group Ltd.)
• Original Assignee: Delphi Technologies, Inc. (Aptiv PLC)
• Inventors: Collier-Hallman, Steven J., Chandy, Ashok, Kleinau, Julie A., Patankar, Ravindra P.
• Granted Patent: US 7,199,549 B2
• Time in Patent Office: Days
• US Class Current: 318/567
• 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;

said controller executing a parameter estimation process responsive to at least one of, said current value, a torque command indicative of a desired torque for said electric machine, a resultant of said parameter estimation process representing a parameter of said electric machine.

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 current value is representative of a torque current for said electric machine.

5. The system of claim 1 wherein said parameter estimation process comprises a feedback estimation methodology.

6. The system of claim 5 wherein said feedback estimation methodology comprises a closed loop compensation for build and life variations in said parameter of said electric machine.

7. The system of claim 5 further including a velocity sensor disposed to measure a velocity of said electric machine and transmitting a velocity signal to said controller and wherein said feedback estimation methodology is responsive to said torque command signal, said current value, and said velocity signal.

8. The system of claim 5 wherein said feedback estimation methodology includes comparing said torque command signal with an estimated torque in a time coherent manner to generate a torque error.

9. The system of claim 8 wherein said estimated torque is responsive to said current value, a velocity signal, and an earlier parameter estimate.

10. The system of claim 9 wherein said earlier parameter estimate is an earlier motor constant estimate.

11. The system of claim 8 wherein said feedback estimation methodology includes an error accumulator, which generates said parameter estimate in response to said torque error.

12. The system of claim 11 wherein said error accumulator comprises a conditional integrator.

13. The system of claim 11 wherein said error accumulator is initialized to a nominal value of said parameter.

14. The system of claim 11 wherein said error accumulator is initialized to a saved value of said error accumulator, said saved value updated with a current output of said error accumulator only if said current output of said error accumulator exhibits a change in excess of a selected threshold.

15. The system of claim 5 wherein said controller receives an estimate good flag.

16. The system of claim 15 wherein said estimate good flag is indicative of a validity of said estimated torque.

17. The system of claim 15 wherein said feedback estimation methodology is responsive to said estimate good flag.

18. The system of claim 17 wherein said feedback estimation methodology is disabled when said estimate good flag indicates an invalid estimated torque.

19. The system of claim 5 wherein said controller receives a rate flag.

20. The system of claim 19 wherein said rate flag is indicative of current dynamics beyond a selected threshold.

21. The system of claim 20 wherein said feedback estimation methodology is disabled when said rate flag indicates current dynamics beyond said selected threshold.

22. The system of claim 21 wherein said selected threshold is two amperes over a 2 millisecond duration.

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

receiving at least one of;

a torque command signal indicative of a desired torque for said electric machine;

a current value;

wherein said estimating is a resultant of a parameter estimation process responsive to said torque command signal and said current value, a resultant of said parameter estimation process representing said parameter of said electric machine.

24. The method of claim 23 wherein said electric machine comprises an electric motor.

25. The method of claim 23 wherein said parameter comprises at least one of a resistance, an inductance, and a motor constant.

26. The method of claim 23 wherein said current value is representative of a torque current for said electric machine.

27. The method of claim 23 wherein said parameter estimation process comprises a feedback estimation methodology.

28. The method of claim 27 wherein said feedback estimation methodology comprises a closed loop compensation for build and life variations in said parameter of said electric machine.

29. The method of claim 27 further including obtaining a velocity signal responsive to a velocity of said electric machine, wherein said feedback estimation methodology is responsive to said torque command signal, said current value, and said velocity signal.

30. The method of claim 27 wherein said feedback estimation methodology includes comparing said torque command signal with an estimated torque in a time coherent manner to generate a torque error.

31. The method of claim 30 wherein said estimated torque is responsive to said current value, a velocity signal, and an earlier parameter estimate.

32. The method of claim 31 wherein said earlier parameter estimate is an earlier motor constant estimate.

33. The method of claim 30 wherein said feedback estimation methodology includes an error accumulator, which generates said parameter estimate in response to said torque error.

34. The method of claim 33 wherein said error accumulator comprises a conditional integrator.

35. The method of claim 33 wherein said error accumulator is initialized to a nominal value of said parameter.

36. The method of claim 33 wherein said error accumulator is initialized to a saved value of said error accumulator, said saved value updated with a current output of said error accumulator only if said current output of said error accumulator exhibits a change in excess of a selected threshold.

37. The method of claim 27 further comprising receiving an estimate good flag.

38. The method of claim 37 wherein said estimate good flag is indicative of a validity of said estimated torque.

39. The method of claim 37 wherein said feedback estimation methodology is responsive to said estimate good flag.

40. The method of claim 39 wherein said feedback estimation methodology is disabled when said estimate good flag indicates an invalid estimated torque.

41. The method of claim 27 further comprising receiving a rate flag.

42. The method of claim 41 wherein said rate flag is indicative of current dynamics beyond a selected threshold.

43. The method of claim 42 wherein said feedback estimation methodology is disabled when said rate flag indicates current dynamics beyond said selected threshold.

44. The method of claim 43 wherein said selected threshold is two amperes over a 2 millisecond duration.

45. 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 at least one of;

a torque command signal indicative of a desired torque for said electric machine;

a current value; and

wherein said estimating is a resultant of a parameter estimation process responsive to at least one of said torque command signal and said current value, a resultant of said parameter estimation process representing said parameter of said electric machine.

46. The storage medium of claim 45 wherein said parameter comprises at least one of a resistance, an inductance, and a motor constant.

47. The storage medium of claim 45 wherein said current value is representative of a torque current for said electric machine.

48. The storage medium of claim 45 wherein said parameter estimation process comprises a feedback estimation methodology.

49. The storage medium of claim 48 wherein said feedback estimation methodology comprises a closed loop compensation for build and life variations in said parameter of said electric machine.

50. The storage medium of claim 48 further including a velocity signal responsive to a velocity of said electric machine, wherein said feedback estimation methodology is responsive to said torque command signal, said current value, and said velocity signal.

51. The storage medium of claim 48 wherein said feedback estimation methodology includes comparing said torque command signal with an estimated torque in a time coherent manner to generate a torque error.

52. The storage medium of claim 51 wherein said estimated torque is responsive to said current value, a velocity signal, and an earlier parameter estimate.

53. The storage medium of claim 52 wherein said earlier parameter estimate is an earlier motor constant estimate.

54. The storage medium of claim 51 wherein said feedback estimation methodology includes an error accumulator, which generates said parameter estimate in response to said torque error.

55. The storage medium of claim 54 wherein said error accumulator comprises a conditional integrator.

56. The storage medium of claim 54 wherein said error accumulator is initialized to a nominal value of said parameter.

57. The storage medium of claim 54 wherein said error accumulator is initialized to a saved value of said error accumulator, said saved value updated with a current output of said error accumulator only if said current output of said error accumulator exhibits a change in excess of a selected threshold.

58. The storage medium of claim 48 further comprising instructions for causing said controller to implement a method further comprising receiving an estimate good flag.

59. The storage medium of claim 58 wherein said estimate good flag is indicative of a validity of said estimated torque.

60. The storage medium of claim 48 further comprising instructions for causing said controller to implement a method further comprising receiving a rate flag.

61. The storage medium of claim 60 wherein said rate flag is indicative of current dynamics beyond a selected threshold.

62. The storage medium of claim 61 wherein said feedback estimation methodology is disabled when said rate flag indicates current dynamics beyond said selected threshold.

63. 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 at least one of;

a torque command signal indicative of a desired torque for said electric machine;

a current value; and

wherein said estimating is a resultant of a parameter estimation process responsive to at least one of said torque command signal and said current value, a resultant of said parameter estimation process representing said parameter of said electric machine.

64. The computer data signal of claim 63 wherein said parameter comprises at least one of a resistance, an inductance, and a motor constant.

65. The computer data signal of claim 63 wherein said current value is representative of a torque current for said electric machine.

66. The computer data signal of claim 63 wherein said parameter estimation process comprises a feedback estimation methodology.

67. The computer data signal of claim 66 wherein said feedback estimation methodology comprises a closed loop compensation for build and life variations in said parameter o f said electric machine.

68. The computer data signal of claim 66 further including a velocity signal responsive to a velocity of said electric machine, wherein said feedback estimation methodology is responsive to said torque command signal, said current value, and said velocity signal.

69. The computer data signal of claim 66 wherein said feedback estimation methodology includes comparing said torque command signal with an estimated torque in a time coherent manner to generate a torque error.

70. The computer data signal of claim 69 wherein said estimated torque is responsive to said current value, a velocity signal, and an earlier parameter estimate.

71. The computer data signal of claim 70 wherein said earlier parameter estimate is an earlier motor constant estimate.

72. The computer data signal of claim 69 wherein said feedback estimation methodology includes an error accumulator, which generates said parameter estimate in response to said torque error.

73. The computer data signal of claim 72 wherein said error accumulator comprises a conditional integrator.

74. The computer data signal of claim 72 wherein said error accumulator is initialized to a nominal value of said parameter.

75. The computer data signal of claim 72 wherein said error accumulator is initialized to a saved value of said error accumulator, said saved value updated with a current output of said error accumulator only if said current output of said error accumulator exhibits a change in excess of a selected threshold.

76. The computer data signal of claim 66 further comprising instructions for causing said controller to implement a method further comprising receiving an estimate good flag.

77. The computer data signal of claim 75 wherein said estimate good flag is indicative of a validity of said estimated torque.

78. The computer data signal of claim 66 further comprising instructions for causing said controller to implement a method further comprising receiving a rate flag.

79. The computer data signal of claim 78 wherein said rate flag is indicative of current dynamics beyond a selected threshold.

80. The computer data signal of claim 79 wherein said feedback estimation methodology is disabled when said rate flag indicates current dynamics beyond said selected threshold.