Active temperature estimation for electric machines

• US 20030076065A1
• Filed: 12/11/2001
• Published: 04/24/2003
• 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. (BorgWarner Incorporated)
• Inventors: Shafer, Daniel W., Kleinau, Julie A., Zuraski, Jeffery A.
• Granted Patent: US 7,071,649 B2
• Time in Patent Office: Days
• US Class Current: 318/567
• 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: G01K 7/42 Circuits effecting compensation of thermal inertia; Circuits for predicting the stationary value of a temperature
• CPC Class Codes: G05B 13/04 involving the use of models or simulators
• CPC Class Codes: H02P 21/14 Estimation or adaptation of machine parameters, e.g. flux, current or voltage
• CPC Class Codes: H02P 23/14 Estimation or adaptation of motor parameters, e.g. rotor time constant, flux, speed, current or voltage

Abstract

A method and system for estimating a temperature of an electric machine comprising obtaining a temperature value responsive to a temperature signal from a temperature sensor, the temperature sensor is operatively connected to and transmitting the temperature signal corresponding to a measured temperature to a controller. The controller executes a temperature estimation process; and is operatively connected to a switching device, where the switching device is operatively connected between the electric machine and a power source, the switching device being responsive to the controller. Also disclosed is a storage medium encoded with a machine-readable computer program code for estimating an operating temperature of an electric machine. The storage medium includes instructions for causing controller to implement method for estimating an operating temperature of an electric machine as described above. Additionally disclosed is a computer data signal embodied in a carrier wave for estimating an operating temperature of an electric machine. The computer data signal comprising code configured to cause a controller to implement a method for estimating an operating temperature of an electric machine as described above.

Claims

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

a temperature sensor operatively connected to and transmitting a temperature signal corresponding to a measured temperature to a controller;

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

said controller executing a temperature estimation process; and

wherein an output of said temperature estimation process represents said temperature of said electric machine.

2. The system of claim 1 wherein said temperature sensor comprises a thermistor.

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

4. The system of claim 1 further comprising said controller including an initialization signal in communication with said temperature estimation process.

5. The system of claim 4 wherein said initialization signal initializes said temperature estimation process to a substrate temperature corresponding to a linearization of said output of said temperature sensor.

6. The system of claim 4 wherein said initialization signal initializes said temperature estimation process by continuing to operate following power down until said temperature estimation process approaches an approximately steady state value.

7. The system of claim 4 wherein said initialization signal initializes said temperature estimation process to an initial value based on temperature estimates responsive to another temperature sensor.

8. The system of claim 7 wherein said another temperature sensor is an engine coolant sensor.

9. The system of claim 7 wherein said initialization signal is responsive to a computed duration of temperature change as a function of said another temperature sensor.

10. The system of claim 9 wherein said temperature estimation process computes a temperature, T_x in accordance with the equation:

11. The system of claim 4 wherein said initialization signal initializes said temperature estimation process to an ambient temperature.

12. The system of claim 4 wherein said initialization signal initializes said temperature estimation process to an ambient temperature estimate.

13. The system of claim 12 wherein said ambient temperature estimate is a resultant of a filter having a cutoff frequency sized to estimate a thermal time constant of said electric machine.

14. The system of claim 12 wherein said ambient temperature estimate is a resultant of a first order, lag filter.

15. The system of claim 14 wherein said first order, lag filter includes a lag frequency range between about 35 μ

Hz and about 80 μ

Hz.

16. The system of claim 4 wherein said temperature estimation process is a resultant of at least one of:

a silicon temperature estimate filter, responsive to said output from said temperature sensor, said silicon temperature estimate filter having an output corresponding to an estimated temperature of said switching device for said electric machine;

a magnet temperature estimate filter, responsive to said output from said temperature sensor, said magnet temperature estimate filter having an output corresponding to an estimated temperature of a magnet associated with said electric machine; and

a copper winding temperature estimate filter responsive to said output from said temperature sensor, said copper winding temperature estimate filter having an output corresponding to an estimated temperature of copper windings associated with said electric machine.

17. The system of claim 16, wherein said silicon temperature estimate filter, said magnet temperature estimate filter, and said copper winding temperature estimate filter are first order, lead-lag filters.

18. The system of claim 17 wherein said silicon temperature estimate filter includes a lag frequency range of between about 53 μ

Hz and about 320 μ

Hz and a lead frequency range of between about 53 μ

Hz and about 160 μ

Hz.

19. The system of claim 17 wherein said magnet temperature estimate filter includes a lag frequency range of between about 35 μ

Hz and about 80 μ

Hz and a lead frequency range of between about 53 μ

Hz and about 160 μ

Hz.

20. The system of claim 17, wherein said copper winding temperature estimate filter includes a lag frequency range of between about 35 μ

Hz and about 80 μ

Hz and a lead frequency range of between about 53 μ

Hz and about 160 μ

Hz.

21. The system of claim 1 further comprising a linearization function, with said output of said temperature sensor being provided to an input of said linearization function mechanism and an output of said linearization function mechanism being provided to said input of said temperature estimation process.

22. The system of claim 1 wherein said temperature estimation process is the resultant of at least one of:

a silicon temperature estimate filter, responsive to said output from said temperature sensor, said silicon temperature estimate filter having an output corresponding to an estimated temperature of said switching device for said electric machine;

a magnet temperature estimate filter, responsive to said output from said temperature sensor, said magnet temperature estimate filter having an output corresponding to an estimated temperature of a magnet associated with said electric machine; and

a copper winding temperature estimate filter responsive to said output from said temperature sensor, said copper winding temperature estimate filter having an output corresponding to an estimated temperature of copper windings associated with said electric machine.

23. The system of claim 22, wherein said silicon temperature estimate filter, said magnet temperature estimate filter, and said copper winding temperature estimate filter are first order, lead-lag filters.

24. The system of claim 23 wherein said silicon temperature estimate filter includes a lag frequency range of between about 53 μ

Hz and about 320 μ

Hz and a lead frequency range of between about 53 μ

Hz and about 160 μ

Hz.

25. The system of claim 23 wherein said magnet temperature estimate filter includes a lag frequency range of between about 35 μ

Hz and about 80 μ

Hz and a lead frequency range of between about 53 μ

Hz and about 160 μ

Hz.

26. The system of claim 23, wherein said copper winding temperature estimate filter includes a lag frequency range of between about 35 μ

Hz and about 80 μ

Hz and a lead frequency range of between about 53 μ

Hz and about 160 μ

Hz.

27. A method for estimating an operating temperature of an electric machine comprising:

obtaining a temperature value responsive to a temperature signal from a temperature sensor;

filtering said temperature signal through a temperature estimation process to generate a temperature estimate; and

wherein said estimating an operating temperature is responsive to said temperature estimate.

28. The method of claim 27 wherein said temperature sensor comprises a thermistor.

29. The method of claim 27 wherein said electric machine comprises an electric motor.

30. The method of claim 27 further comprising initializing said temperature estimation process with an initialization signal.

31. The method of claim 30, wherein said initialization signal initializes said temperature estimation process to a substrate temperature corresponding to a linearized output of said temperature sensor.

32. The method of claim 30 wherein said initialization signal initializes said temperature estimation process by continuing to operate following power down until said temperature estimation process approaches an approximately steady state value.

33. The method of claim 30 wherein said initialization signal initializes said temperature estimation process to an initial value based on temperature estimates responsive to another temperature sensor.

34. The method of claim 33 wherein said another temperature sensor is an engine coolant sensor.

35. The method of claim 33 wherein said initialization signal is responsive to a computed duration of temperature change as a function of said another temperature sensor.

36. The method of claim 35 wherein said temperature estimation process computes a temperature T_x in accordance with the equation:

37. The method of claim 30, wherein said initialization signal initializes said temperature estimation process to an ambient temperature.

38. The method of claim 30, wherein said initialization signal initializes said temperature estimation process to an ambient temperature estimate.

39. The method of claim 38, wherein said ambient temperature estimate comprises a filter having a cutoff frequency sized to estimate a thermal time constant of said electric machine.

40. The method of claim 38, wherein said ambient temperature estimate comprises a first order, lag filter.

41. The method of claim 40 wherein said first order, lag filter includes a lag frequency range of between about 35 μ

Hz and about 80 μ

Hz.

42. The method of claim 30 wherein said temperature estimation process comprises at least one of:

a silicon temperature estimate filter, responsive to said output from said temperature sensor, said silicon temperature estimate filter having an output corresponding to an estimated temperature of a switching device for said electric machine;

a magnet temperature estimate filter, responsive to said output from said temperature sensor, said magnet temperature estimate filter having an output corresponding to an estimated temperature of a magnet associated with said electric machine; and

a copper winding temperature estimate filter responsive to said output from said temperature sensor, said copper winding temperature estimate filter having an output corresponding to an estimated temperature of copper windings associated with said electric machine.

43. The method of claim 42, wherein said silicon temperature estimate filter, said magnet temperature estimate filter, and said copper winding temperature estimate filter are first order, lead-lag filters.

44. The method of claim 43 wherein said silicon temperature estimate filter includes a lag frequency range of between about 53 μ

Hz and about 320 μ

Hz and a lead frequency range of between about 53 μ

Hz and about 160 μ

Hz.

45. The method of claim 43 wherein said magnet temperature estimate filter includes a lag frequency range between about 35 μ

Hz and about 80 μ

Hz and a lead frequency range between about 53 μ

Hz and about 160 μ

Hz.

46. The method of claim 43, wherein said copper winding temperature estimate filter includes a lag frequency range between about 35 μ

Hz and about 80 μ

Hz and a lead frequency range between about 53 μ

Hz and about 160 μ

Hz.

47. The method of claim 27 further comprising linearizing said temperature signal.

48. The method of claim 47 wherein said linearizing comprises processing via a linearization function mechanism interposed between said temperature sensor and said temperature estimation process, with said output of said temperature sensor being connected to an input of said linearization function mechanism and an output of said linearization function mechanism being connected to said input of said temperature estimation process.

49. The method of claim 27 wherein said temperature estimation process comprises at least one of:

a silicon temperature estimate filter, responsive to said output from said temperature sensor, said silicon temperature estimate filter having an output corresponding to an estimated temperature of a switching device for said electric machine;

a magnet temperature estimate filter, responsive to said output from said temperature sensor, said magnet temperature estimate filter having an output corresponding to an estimated temperature of a magnet associated with said electric machine; and

a copper winding temperature estimate filter responsive to said output from said temperature sensor, said copper winding temperature estimate filter having an output corresponding to an estimated temperature of copper windings associated with said electric machine.

50. The method of claim 49, wherein said silicon temperature estimate filter, said magnet temperature estimate filter, and said copper winding temperature estimate filter are first order, lead-lag filters.

51. The method of claim 50 wherein said silicon temperature estimate filter includes a lag frequency range between about 53 μ

Hz and about 320 μ

Hz and a lead frequency range between about 53 μ

Hz and about 160 μ

Hz.

52. The method of claim 50 wherein said magnet temperature estimate filter includes a lag frequency range between about 35 μ

Hz and about 80 μ

Hz and a lead frequency range between about 53 μ

Hz and about 160 μ

Hz.

53. The method of claim 50, wherein said copper winding temperature estimate filter includes a lag frequency range of between about 35 μ

Hz and about 80 μ

Hz and a lead frequency range between about 53 μ

Hz and about 160 μ

Hz.

54. A storage medium encoded with computer program code,

said code including instructions for causing controller to implement a method for estimating an operating temperature of an electric machine, the method comprising:

obtaining a temperature value responsive to a temperature signal from a temperature sensor;

filtering said temperature signal through a temperature estimation process to generate a temperature estimate; and

wherein said estimating an operating temperature is responsive to said temperature estimate.

55. The storage medium of claim 54 further comprising instructions for causing controller to implement a method further comprising initializing said temperature estimation process with an initialization signal.

56. The storage medium of claim 55, wherein said initialization signal initializes said temperature estimation process to a substrate temperature corresponding to a linearized output of said temperature sensor.

57. The storage medium of claim 55 wherein said initialization signal initializes said temperature estimation process by continuing to operate following power down until said temperature estimation process approaches an approximately steady state value.

58. The storage medium of claim 55 wherein said initialization signal initializes said temperature estimation process to an initial value based on temperature estimates responsive to another temperature sensor.

59. The storage medium of claim 55, wherein said initialization signal initializes said temperature estimation process to an ambient temperature.

60. The storage medium of claim 55, wherein said initialization signal initializes said temperature estimation process to an ambient temperature estimate.

61. The storage medium of claim 55 wherein said temperature estimation process comprises at least one of:

a silicon temperature estimate filter, responsive to said output from said temperature sensor, said silicon temperature estimate filter having an output corresponding to an estimated temperature of a switching device for said electric machine;

a magnet temperature estimate filter, responsive to said output from said temperature sensor, said magnet temperature estimate filter having an output corresponding to an estimated temperature of a magnet associated with said electric machine; and

a copper winding temperature estimate filter responsive to said output from said temperature sensor, said copper winding temperature estimate filter having an output corresponding to an estimated temperature of copper windings associated with said electric machine.

62. The storage medium of claim 54 further comprising instructions for causing controller to implement a method further comprising linearizing said temperature signal.

63. The storage medium of claim 62 wherein said linearizing comprises processing via a linearization function mechanism interposed between said temperature sensor and said temperature estimation process, with said output of said temperature sensor being connected to an input of said linearization function mechanism and an output of said linearization function mechanism being connected to said input of said temperature estimation process.

64. The storage medium of claim 54 wherein said temperature estimation process comprises at least one of:

a silicon temperature estimate filter, responsive to said output from said temperature sensor, said silicon temperature estimate filter having an output corresponding to an estimated temperature of a switching device for said electric machine;

a magnet temperature estimate filter, responsive to said output from said temperature sensor, said magnet temperature estimate filter having an output corresponding to an estimated temperature of a magnet associated with said electric machine; and

a copper winding temperature estimate filter responsive to said output from said temperature sensor, said copper winding temperature estimate filter having an output corresponding to an estimated temperature of copper windings associated with said electric machine.

65. The storage medium of claim 64, wherein said silicon temperature estimate filter, said magnet temperature estimate filter, and said copper winding temperature estimate filter are first order, lead-lag filters.

66. The storage medium of claim 65 wherein said silicon temperature estimate filter includes a lag frequency range between about 53 μ

Hz and about 320 μ

Hz and a lead frequency range between about 53 μ

Hz and about 160 μ

Hz.

67. The storage medium of claim 66 wherein said magnet temperature estimate filter includes a lag frequency range between about 35 μ

Hz and about 80 μ

Hz and a lead frequency range between about 53 μ

Hz and about 160 μ

Hz.

68. The storage medium of claim 65, wherein said copper winding temperature estimate filter includes a lag frequency range between about 35 μ

Hz and about 80 μ

Hz and a lead frequency range between about 53 μ

Hz and about 160 μ

Hz.

69. 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 an operating temperature of an electric machine, the method comprising;

obtaining a temperature value responsive to a temperature signal from a temperature sensor;

filtering said temperature signal through a temperature estimation process to generate a temperature estimate; and

wherein said estimating an operating temperature is responsive to said temperature estimate.

70. The computer data signal of claim 69 further comprising instructions for causing controller to implement a method further comprising initializing said temperature estimation process with an initialization signal.

71. The computer data signal of claim 70, wherein said initialization signal initializes said temperature estimation process to a substrate temperature corresponding to a linearized output of said temperature sensor.

72. The computer data signal of claim 70 wherein said initialization signal initializes said temperature estimation process by continuing to operate following power down until said temperature estimation process approaches an approximately steady state value.

73. The computer data signal of claim 70 wherein said initialization signal initializes said temperature estimation process to an initial value based on temperature estimates responsive to another temperature sensor.

74. The computer data signal of claim 70, wherein said initialization signal initializes said temperature estimation process to an ambient temperature.

75. The computer data signal of claim 70, wherein said initialization signal initializes said temperature estimation process to an ambient temperature estimate.

76. The computer data signal of claim 70 wherein said temperature estimation process comprises at least one of:

a silicon temperature estimate filter, responsive to said output from said temperature sensor, said silicon temperature estimate filter having an output corresponding to an estimated temperature of a switching device for said electric machine;

a magnet temperature estimate filter, responsive to said output from said temperature sensor, said magnet temperature estimate filter having an output corresponding to an estimated temperature of a magnet associated with said electric machine; and

a copper winding temperature estimate filter responsive to said output from said temperature sensor, said copper winding temperature estimate filter having an output corresponding to an estimated temperature of copper windings associated with said electric machine.

77. The computer data signal of claim 69 further comprising instructions for causing controller to implement a method further comprising linearizing said temperature signal.

78. The computer data signal of claim 77 wherein said linearizing comprises processing via a linearization function mechanism interposed between said temperature sensor and said temperature estimation process, with said output of said temperature sensor being connected to an input of said linearization function mechanism and an output of said linearization function mechanism being connected to said input of said temperature estimation process.

79. The computer data signal of claim 69 wherein said temperature estimation process comprises at least one of:

a silicon temperature estimate filter, responsive to said output from said temperature sensor, said silicon temperature estimate filter having an output corresponding to an estimated temperature of a switching device for said electric machine;

a magnet temperature estimate filter, responsive to said output from said temperature sensor, said magnet temperature estimate filter having an output corresponding to an estimated temperature of a magnet associated with said electric machine; and

a copper winding temperature estimate filter responsive to said output from said temperature sensor, said copper winding temperature estimate filter having an output corresponding to an estimated temperature of copper windings associated with said electric machine.

80. The computer data signal of claim 79, wherein said silicon temperature estimate filter, said magnet temperature estimate filter, and said copper winding temperature estimate filter are first order, lead-lag filters.

81. The computer data signal of claim 80 wherein said silicon temperature estimate filter includes a lag frequency range between about 53 μ

Hz and about 320 μ

Hz and a lead frequency range between about 53 μ

Hz and about 160 μ

Hz.

82. The computer data signal of claim 81 wherein said magnet temperature estimate filter includes a lag frequency range between about 35 μ

Hz and about 80 μ

Hz and a lead frequency range between about 53 μ

Hz and about 160 μ

Hz.

83. The computer data signal of claim 80, wherein said copper winding temperature estimate filter includes a lag frequency range between about 35 μ

Hz and about 80 μ

Hz and a lead frequency range between about 53 μ

Hz and about 160 μ

Hz.