Feedforward parameter estimation for electric machines

• US 20030076064A1
• Filed: 12/11/2001
• Published: 04/24/2003
• Est. Priority Date: 08/17/2001
• Status: Abandoned Application

• Current Assignee: Delphi Technologies, Inc. (BorgWarner Incorporated)
• Original Assignee: Delphi Technologies, Inc. (BorgWarner Incorporated)
• Inventors: Shafer, Daniel W., Kleinau, Julie A., Zuraski, Jeffery A.
• Application Number:
  US10/013,905
• Publication Number:
  US 20030076064A1
• Time in Patent Office: Days
• US Class Current: 318/567
• CPC Class Codes: B62D 5/0481 monitoring the steering system, e.g. failures
• 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 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 parameter of an electric machine, including a controller and a switching device, the controller responsive to at least one of: a current sensor, and a temperature sensor. Where the controller executes a parameter estimation process, which is responsive to at least one of: a current value and a temperature estimate 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: the temperature sensor operatively connected to and transmitting a temperature signal corresponding to a measured temperature to a controller, which executes the temperature estimation process responsive to a temperature signal from the 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;

at least one of;

a current sensor operatively connected to and transmitting a current value indicative of a current in said electric machine;

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

said controller executing a parameter estimation process responsive to at least one of, a temperature value responsive to said temperature signal, said current value, 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 temperature sensor comprises a thermistor.

6. The system of claim 1 wherein said controller executes a process for linearizing said temperature signal.

7. The system of claim 6 wherein said linearizing comprises processing via a linearization function mechanism, 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 an input of said parameter estimation process.

8. The system of claim 1 wherein said parameter estimation process includes a feedforward estimation methodology responsive to said temperature value.

9. The system of claim 8 wherein said feedforward estimation methodology comprises compensation for temperature variations of said parameter, said compensation employing a temperature coefficient of said parameter.

10. The system of claim 9 wherein said temperature value is responsive to a temperature estimation process.

11. The system of claim 10 wherein said temperature estimation process is implemented by 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.

12. The system of claim 11 wherein said silicon temperature estimate filter, said magnet temperature estimate filter, and said copper winding temperature estimate filter are first order, lead-lag filters.

13. The system of claim 12 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.

14. The system of claim 12 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.

15. The system of claim 12 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.

16. The system of claim 10 further comprising an initialization signal in communication with said controller.

17. The system of claim 16 wherein said initialization signal initializes said temperature estimation process to a substrate temperature corresponding to a linearized output of said temperature sensor.

18. The system of claim 16 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.

19. The system of claim 16 wherein said initialization signal initializes said temperature estimation process to an initial value based on temperature estimates responsive to another temperature sensor.

20. The system of claim 19 wherein said another temperature sensor is an engine coolant sensor.

21. The system of claim 16 wherein said initialization signal is responsive to a computed duration of temperature change as a function of said another temperature sensor.

22. The system of claim 21 wherein said temperature estimation process computes a temperature T_x in accordance with the equation:

23. The system of claim 16 wherein said initialization signal initializes said temperature estimation process to an ambient temperature.

24. The system of claim 16 wherein said initialization signal initializes said temperature estimation process to an ambient temperature estimate.

25. The system of claim 24 wherein said ambient temperature estimate comprises a filter having a cutoff frequency sized to estimate a thermal time constant of said electric machine.

26. The system of claim 25 wherein said ambient temperature estimate comprises a first order, lag filter.

27. The system of claim 26 wherein said first order, lag filter includes a lag frequency range between about 35 μ

Hz and about 80 μ

Hz.

28. The system of claim 16 wherein said temperature estimation process is implemented by 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.

29. The system of claim 28 wherein said silicon temperature estimate filter, said magnet temperature estimate filter, and said copper winding temperature estimate filter are first order, lead-lag filters.

30. The system of claim 29 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.

31. The system of claim 29 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.

32. The system of claim 29 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 Hz.

33. The system of claim 10 further comprising initializing said parameter estimate with an initialization signal said initialization signal in communication with said temperature estimation process.

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

receiving at least one of;

a current value;

a temperature value

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

35. The method of claim 34 wherein said electric machine comprises an electric motor.

36. The method of claim 34 wherein said parameter comprises at least one of a resistance, an inductance, and a motor constant.

37. The method of claim 34 wherein said current value is representative of a torque current for said electric machine.

38. The method of claim 34 wherein said temperature value is responsive to a temperature signal from a temperature sensor.

39. The method of claim 38 wherein said temperature sensor comprises a thermistor.

40. The method of claim 38 further comprising linearizing said temperature signal.

41. The method of claim 40 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.

42. The method of claim 34 wherein said parameter estimation process includes a feedforward estimation methodology responsive to said temperature value.

43. The method of claim 42 wherein said feedforward estimation methodology comprises compensation for temperature variations of said parameter, said compensation employing a temperature coefficient of said parameter.

44. The method of claim 43 wherein said temperature value is responsive to a temperature estimation process.

45. The method of claim 44 wherein said temperature estimation process further 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.

46. The method of claim 45 wherein said silicon temperature estimate filter, said magnet temperature estimate filter, and said copper winding temperature estimate filter are first order, lead-lag filters.

47. The method of claim 46 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.

48. The method of claim 46 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.

49. The method of claim 46 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.

50. The method of claim 44 further comprising initializing said temperature estimation process with an initialization signal.

51. The method of claim 50 wherein said initialization signal initializes said temperature estimation process to a substrate temperature corresponding to a linearized output of said temperature sensor.

52. The method of claim 50 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.

53. The method of claim 50 wherein said initialization signal initializes said temperature estimation process to an initial value based on temperature estimates responsive to another temperature sensor.

54. The method of claim 53 wherein said another temperature sensor is an engine coolant sensor.

55. The method of claim 50 wherein said initialization signal is responsive to a computed duration of temperature change as a function of said another temperature sensor.

56. The method of claim 55 wherein said temperature estimation process computes a temperature T_x in accordance with the equation:

57. The method of claim 50 wherein said initialization signal initializes said temperature estimation process to an ambient temperature.

58. The method of claim 50 wherein said initialization signal initializes said temperature estimation process to an ambient temperature estimate.

59. The method of claim 58 wherein said ambient temperature estimate comprises a filter having a cutoff frequency sized to estimate a thermal time constant of said electric machine.

60. The method of claim 59 wherein said ambient temperature estimate comprises a first order, lag filter.

61. The method of claim 60 wherein said first order, lag filter includes a lag frequency range between about 35 μ

Hz and about 80 μ

Hz.

62. The method of claim 50 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.

63. The method of claim 62 wherein said silicon temperature estimate filter, said magnet temperature estimate filter, and said copper winding temperature estimate filter are first order, lead-lag filters.

64. The method of claim 63 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.

65. The method of claim 63 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.

66. The method of claim 63 wherein said copper winding temperature estimate filter includes 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.

67. The method of claim 44 further comprising initializing said parameter estimate with an initialization signal said initialization signal in communication with said temperature estimation process.

68. 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 current value; and

a temperature value

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

69. The storage medium of claim 68 wherein said parameter comprises at least one of a resistance, an inductance, and a motor constant.

70. The storage medium of claim 68 wherein said current value is representative of a torque current for said electric machine.

71. The storage medium of claim 68 wherein said temperature value is responsive to a temperature signal from a temperature sensor.

72. The storage medium of claim 71 further comprising instructions for causing said controller to implement a method further comprising linearizing said temperature signal.

73. The storage medium of claim 68 wherein said parameter estimation process includes a feedforward estimation methodology responsive to said temperature value and wherein said temperature value is responsive to a temperature estimation process.

74. The storage medium of claim 73 wherein said feedforward estimation methodology comprises compensation for temperature variations of said parameter, said compensation employing a temperature coefficient of said parameter.

75. The storage medium of claim 74 wherein said temperature estimation process further 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.

76. The storage medium of claim 73 further comprising instructions for causing said controller to implement a method further comprising initializing said temperature estimation process with an initialization signal.

77. The storage medium of claim 76 wherein said initialization signal initializes said temperature estimation process to a substrate temperature corresponding to a linearized output of said temperature sensor.

78. The storage medium of claim 76 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.

79. The storage medium of claim 76 wherein said initialization signal is responsive to a computed duration of temperature change as a function of said another temperature sensor.

80. The storage medium of claim 76 wherein said initialization signal initializes said temperature estimation process to an ambient temperature.

81. The storage medium of claim 76 wherein said initialization signal initializes said temperature estimation process to an ambient temperature estimate.

82. The storage medium of claim 76 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.

83. The storage medium of claim 74 further comprising instructions for causing said controller to implement a method further comprising initializing said parameter estimate with an initialization signal said initialization signal in communication with said temperature estimation process.

84. 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 current value; and

a temperature value

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

85. The computer data signal of claim 84 wherein said parameter comprises at least one of a resistance, an inductance, and a motor constant.

86. The computer data signal of claim 84 wherein said current value is representative of a torque current for said electric machine.

87. The computer data signal of claim 84 wherein said temperature value is responsive to a temperature signal from a temperature sensor.

88. The computer data signal of claim 87 further comprising instructions for causing said controller to implement a method further comprising linearizing said temperature signal.

89. The computer data signal of claim 84 wherein said parameter estimation process includes a feedforward estimation methodology responsive to said temperature value and wherein said temperature value is responsive to a temperature estimation process.

90. The computer data signal of claim 89 wherein said feedforward estimation methodology comprises compensation for temperature variations of said parameter, said compensation employing a temperature coefficient of said parameter.

91. The computer data signal of claim 90 wherein said temperature estimation process further 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.

92. The computer data signal of claim 89 further comprising instructions for causing said controller to implement a method further comprising initializing said temperature estimation process with an initialization signal.

93. The computer data signal of claim 92 wherein said initialization signal initializes said temperature estimation process to a substrate temperature corresponding to a linearized output of said temperature sensor.

94. The computer data signal of claim 92 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.

95. The computer data signal of claim 92 wherein said initialization signal is responsive to a computed duration of temperature change as a function of said another temperature sensor.

96. The computer data signal of claim 92 wherein said initialization signal initializes said temperature estimation process to an ambient temperature.

97. The computer data signal of claim 92 wherein said initialization signal initializes said temperature estimation process to an ambient temperature estimate.

98. The computer data signal of claim 92 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.

99. The computer data signal of claim 90 further comprising instructions for causing said controller to implement a method further comprising initializing said parameter estimate with an initialization signal said initialization signal in communication with said temperature estimation process.