AC drive system for electrically operated vehicle

• US 20060108956A1
• Filed: 10/27/2005
• Published: 05/25/2006
• Est. Priority Date: 10/28/2004
• Status: Active Grant

• Current Assignee: Textron Inc
• Original Assignee: Textron Inc
• Inventors: Bell, Oliver A., Clark, Warren
• Granted Patent: US 7,332,881 B2
• Time in Patent Office: Days
• US Class Current: 318/139
• CPC Class Codes: B60L 15/10 for automatic control superimposed on human control to limit the acceleration of the vehicle, e.g. to prevent excessive motor current electric devices for safety purposes B60L3/00
• CPC Class Codes: B60L 15/20 for control of the vehicle or its driving motor to achieve a desired performance, e.g. speed, torque, programmed variation of speed
• CPC Class Codes: B60L 2200/22 Microcars, e.g. golf cars
• CPC Class Codes: B60L 2210/20 AC to AC converters
• CPC Class Codes: B60L 2220/30 Universal machines
• CPC Class Codes: B60L 2250/26 by pedal actuation
• CPC Class Codes: B60L 2260/28 Four wheel or all wheel drive
• CPC Class Codes: B60L 3/108 whilst braking, i.e. ABS
• CPC Class Codes: B60L 3/12 Recording operating variables ; Monitoring of operating variables
• CPC Class Codes: B60L 50/51 characterised by AC-motors
• CPC Class Codes: B60L 53/14 Conductive energy transfer
• CPC Class Codes: B60L 7/14 for vehicles propelled by ac motors
• CPC Class Codes: B60L 7/26 Controlling the braking effect
• CPC Class Codes: B60T 13/586 the retarders being of the electric type
• CPC Class Codes: B60W 10/08 including control of electric propulsion units, e.g. motors or generators
• CPC Class Codes: B60W 10/18 including control of braking systems
• CPC Class Codes: H04L 2012/40215 Controller Area Network CAN
• CPC Class Codes: H04L 2012/40273 the transportation system being a vehicle
• 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
• CPC Class Codes: Y02T 10/72 : Electric energy management in electromobility
• CPC Class Codes: Y02T 90/12 : Electric charging stations
• CPC Class Codes: Y02T 90/14 : Plug-in electric vehicles

Abstract

A drive system is provided for a utility vehicle and includes an alternating-current (AC) motor for providing a drive torque. An AC motor controller receives a battery voltage signal, throttle pedal position signal, brake pedal position signal, key switch signal, forward/neutral/reverse (FNR) signal, and run/tow signal indicative of the utility vehicle being configured to be driven and being configured to be towed. The AC motor controller generates an AC drive signal for the AC motor, wherein the AC drive signal is based on the battery voltage signal, throttle pedal position signal, brake pedal position signal, key switch signal, FNR signal, and run/tow signal.

Claims

1. A drive system for a utility vehicle, comprising:

an alternating-current (AC) motor for providing a drive torque; and

an AC motor controller that receives a battery voltage signal, a throttle pedal position signal, a brake pedal position signal, a key switch signal, a forward/neutral/reverse (FNR) signal, and a run/tow signal indicative of the utility vehicle being configured to be driven and being configured to be towed, wherein the AC motor controller generates an AC drive signal for the AC motor; and

wherein the AC drive signal is based on the battery voltage signal, throttle pedal position signal, brake pedal position signal, key switch signal, FNR signal, and run/tow signal.

2. The drive system of claim 1 wherein the AC motor includes one of a an induction motor and a permanent magnet motor.

3. The drive system of claim 2 wherein the AC motor is a three-phase, 4-pole, brushless motor.

4. The drive system of claim 2 wherein the AC motor includes a wound stator and a permanent magnet rotor.

5. The drive system of claim 4 wherein the permanent magnets include rare earth magnets.

6. The drive system of claim 1 wherein the AC motor controller further includes a media drive for receiving removable storage media including Compact Discs (CDs), Digital Versatile Discs (DVDs), magnetic media, and memory cards.

7. The drive system of claim 1 wherein the AC motor controller further receives a brake full stroke signal and a throttle enable signal.

8. The drive system of claim 1 wherein the AC motor controller further generates a warning signal.

9. The drive system of claim 1 wherein the AC drive signal includes a 3-phase AC drive signal.

10. The drive system of claim 1 wherein the AC drive signal includes at least one of a pulse width modulation signal and a pulse frequency modulation signal.

11. The drive system of claim 1 wherein the AC motor controller determines a maximum speed of the AC motor based on the battery voltage signal.

12. The drive system of claim 1 wherein the AC motor controller determines a maximum speed of the AC motor based on the tow switch signal and the FNR signal.

13. The drive system of claim 1 wherein the AC motor controller further generates a status signal that is communicated to a display.

14. The drive system of claim 13 wherein the status signal indicates at least one of a battery condition, an amp-hour indication, error codes, and a reverse drive condition.

15. The drive system of claim 13 wherein the display includes at least one of light emitting diodes (LEDs), a numeric display, and an alphanumeric display.

16. The drive system of claim 1 wherein the AC motor controller generates the AC drive signal when the key switch is in an on position, the FNR switch is in one of the forward and reverse positions, the tow switch is in the run position, the brake signal is indicative of 0% braking command, and a battery state of charge (SOC) is greater than a predetermined SOC.

17. The drive system of claim 1 wherein the AC motor controller slows the AC motor when the brake signal indicates greater than 0% braking command regardless of the battery voltage signal, throttle pedal position signal, run/tow signal, and FNR signal.

18. The drive system of claim 1 wherein the AC motor controller determines a SOC of a battery and determines a maximum speed of the AC motor based on the SOC.

19. The drive system of claim 1 further comprising a contactor that selectively connects the AC drive signal and the AC motor, and wherein the AC motor controller further generates a PWM contactor control signal that is communicated to the contactor wherein the AC motor controller generates the contactor control signal at a first PWM duty cycle when closing the contactor and generates the contactor control signal at a second PWM duty cycle after the contactor is closed.

20. The drive system of claim 1 further comprising a brake that selectively slows the AC motor and wherein the AC motor controller further generates a brake control signal that is communicated to the brake wherein the AC motor controller generates the brake control signal at a first PWM duty cycle when applying the brake and generates the brake control signal at a second PWM duty cycle after the brake is applied.

21. The drive system of claim 20 wherein the brake includes a parking brake that is applied when the AC motor is stopped.

22. The drive system of claim 1 wherein the AC motor controller reduces the speed of the AC motor at a predetermined rate when the brake signal indicates 0% braking command and the throttle signal indicates 0% throttle command.

23. The drive system of claim 1 wherein the AC motor controller minimizes the drive torque in forward and reverse directions when the run/tow signal indicates the utility vehicle is configured to be towed.

24. The drive system of claim 1 further comprising a rechargeable battery for providing the AC motor controller with a source of electrical energy wherein the rechargeable battery type includes one of lithium ion, nickel cadmium, nickel metal hydride, and lead-acid.

25. The drive system of claim 24 wherein the AC motor controller minimizes current flow through the rechargeable battery when the run/tow signal indicates the utility vehicle is configured to be towed.

26. The drive system of claim 24 wherein the AC motor controller recharges the rechargeable battery with energy received from the AC motor.

27. The drive system of claim 26 wherein the AC motor controller determines a percentage of the energy to provide to the rechargeable battery based on battery pack type, battery pack age, and rate of energy consumption.

28. The drive system of claim 1 further comprising a brake for slowing the utility vehicle and wherein the AC motor controller generates a brake signal for controlling the brake based on the brake position signal, the key switch signal, and the run/tow signal.

29. The drive system of claim 1 wherein the AC motor controller further includes a communication bus interface for communicating data.

30. The drive system of claim 29 wherein the data includes real-time control data.

31. The drive system of claim 29 wherein the communication bus interface is compatible with one of a Controller Area Network (CAN), RS-232, RS-422, universal serial bus (USB), serial, parallel, wireless, Bluetooth, and optical formats.

32. The drive system of claim 30 wherein the real-time control data includes at least one of the battery voltage signal, throttle pedal position signal, brake pedal position signal, key switch signal, FNR signal, and run/tow signal.

33. The drive system of claim 29 further comprising a battery charger that includes a second communication bus interface for communicating a battery state of charge (SOC) with the communication bus interface of the AC motor controller.

34. The drive system of claim 1 further comprising a locking differential that receives and redirects the drive torque to a pair of axles.

35. The drive system of claim 34 wherein the locking differential locks and unlocks in accordance with a differential control signal that is generated by the AC motor controller.

36. The drive system of claim 35 wherein the AC motor controller generates the differential control signal at a first PWM duty cycle when locking the locking differential and generates the differential control signal at a second PWM duty cycle after the locking differential is locked.

37. The drive system of claim 1 further comprising a plurality of wheel speed signals and wherein the AC drive signal is further based on the wheel speed signals.

38. The drive system of claim 37 wherein the AC motor controller includes at least one of an antilock braking system and a traction control system that receive the wheel speed signals and limit acceleration and deceleration of the AC motor.

39. The drive system of claim 38 wherein the traction control system limits the acceleration and deceleration based on comparing wheel speed signals associated with a respective driven wheel and a non-driven wheel.

40. The drive system of claim 1 comprising a second AC motor for providing a second drive torque wherein the AC motor controller communicates a second AC drive signal with the second AC motor and wherein the second AC drive signal is based on an operating condition of the AC motor.

41. A method of operating a drive system for a utility vehicle, comprising:

providing a drive torque; and

receiving a battery voltage signal, a throttle pedal position signal, a brake pedal position signal, a key switch signal, a forward/neutral/reverse (FNR) signal, and a run/tow signal indicative of the utility vehicle being configured to be driven and being configured to be towed;

generating an AC drive signal based on the battery voltage signal, throttle pedal position signal, brake pedal position signal, key switch signal, FNR signal, and run/tow signal; and

converting the AC drive signal to a drive torque for propelling the utility vehicle.

42. The method of claim 41 wherein generating the AC drive signal includes generating a 3-phase AC drive signal.

43. The method of claim 41 further comprising recording values of at least one of said battery voltage signal, throttle pedal position signal, brake pedal position signal, key switch signal, FNR signal, and run/tow signal.

44. The method of claim 41 further comprising receiving a brake full stroke signal and a throttle enable signal.

45. The method of claim 41 further comprising generating a warning signal based on at least one of said battery voltage signal, throttle pedal position signal, brake pedal position signal, key switch signal, FNR signal, and run/tow signal

46. The method of claim 41 wherein the AC drive signal includes at least one of a pulse width modulation signal and a pulse frequency modulation signal.

47. The method of claim 41 further comprising determining a maximum frequency of the AC drive signal based on the battery voltage signal.

48. The method of claim 41 further comprising determining a maximum frequency of the AC drive signal based on the tow switch signal and the FNR signal.

49. The method of claim 41 further comprising generating a status signal and displaying a status indication based on the status signal.

50. The method of claim 49 wherein the status signal indicates at least one of a battery condition, an amp-hour indication, error codes, and a reverse drive condition.

51. The method of claim 41 further comprising generating the AC drive signal when the key switch signal indicates an on position, the FNR signal indicates one of the forward and reverse positions, the run/tow signal indicates a run position, the brake signal indicates a 0% braking command, and a battery state of charge (SOC) is greater than a predetermined SOC.

52. The method of claim 41 further comprising reducing a frequency of the AC drive signal when the brake signal indicates greater than 0% braking command regardless of the battery voltage signal, throttle pedal position signal, run/tow signal, and FNR signal.

53. The method of claim 41 further comprising determining a battery SOC and determining a maximum frequency of the AC drive signal based on the SOC.

54. The method of claim 41 further comprising selectively applying the AC drive signal to the converting step.

55. The method of claim 41 further comprising:

generating a brake control signal at a first PWM duty cycle for a predetermined time and at a second PWM duty cycle thereafter while said brake signal indicates greater than 0% braking command.

56. The method of claim 41 further comprising reducing a frequency of the AC drive signal when the brake signal indicates 0% braking command and the throttle signal indicates 0% throttle command.

57. The method of claim 41 further comprising minimizing the drive torque in forward and reverse directions when the run/tow signal indicates a tow position.

58. The method of claim 41 further comprising minimizing changing a battery state of charge (SOC) when the run/tow signal indicates a tow position.

59. The method of claim 41 further comprising converting kinetic energy of the utility vehicle to electrical energy for increasing a battery state of charge (SOC).

60. The method of claim 59 further comprising determining a percentage of the kinetic energy to convert based on a battery pack type, battery pack age, and rate of energy consumption.

61. The method of claim 41 further comprising braking the utility vehicle based on at least one of the brake position signal, the key switch signal, and the run/tow signal.

62. The method of claim 41 further comprising communicating control data from the utility vehicle, the control data including at least one of the battery voltage signal, throttle pedal position signal, brake pedal position signal, key switch signal, FNR signal, and run/tow signal.

63. The method of claim 62 wherein the control data includes real-time control data.

64. The method of claim 62 further comprising recharging the utility vehicle based on battery state of charge (SOC) data received via said communicating step.

65. The method of claim 41 further comprising receiving and selectively redirecting the drive torque to a pair of axles.

66. The method of claim 41 further comprising receiving a plurality of wheel speed signals and wherein the AC drive signal is further based on the wheel speed signals.

67. The method of claim 66 wherein a rate of change of the AC drive signal frequency is less than a rate of change limit based on the wheel speed signals.

68. The method of claim 67 wherein the rate of change limit is based on comparing wheel speed signals associated with a respective driven wheel and a non-driven wheel.

69. The method of claim 41 further comprising:

generating a second AC drive signal based on an outcome of said step of converting said AC drive signal; and

converting said second AC drive signal to a second drive torque for driving the utility vehicle.

70. The method of claim 69 further comprising the step of generating the AC drive signal includes generating a 3-phse AC drive signal.

71. A drive system for a utility vehicle including a plurality of wheels, comprising:

a plurality of alternating-current (AC) motors, each providing drive torque for an associated one of the wheels;

an AC motor controller that receives a battery voltage signal, a throttle pedal position signal, a brake pedal position signal, a key switch signal, a forward/neutral/reverse (FNR) signal, and a run/tow signal indicative of the utility vehicle being configured to be driven and being configured to be towed, wherein the AC motor controller generates a plurality of AC drive signals for associated ones of the AC motors; and

wherein the AC drive signals are based on the battery voltage signal, throttle pedal position signal, brake pedal position signal, key switch signal, FNR signal, and run/tow signal.

72. The drive system of claim 71 further comprising a steering sensor that generates a steering signal that communicates with the AC motor controller and wherein the AC drive signals are further based on the steering signal.

73. A utility vehicle comprising:

a plurality of wheel supporting the vehicle, at least one wheel being a drive wheel;

an alternating-current (AC) motor for providing a drive torque to the drive wheel; and

an AC motor controller that receives a plurality of input, the motor controller generating an AC drive signal for the AC motor;

wherein the AC drive signal is generated in accordance with at least a battery voltage signal, a throttle pedal position signal, and a brake pedal position signal.

74. The drive system of claim 73 wherein the AC motor includes one of an induction motor and a permanent magnet motor.

75. The drive system of claim 73 wherein the AC motor is a three-phase, 4-pole, brushless motor.

76. The drive system of claim 75 wherein the AC motor includes a wound stator and a permanent magnet rotor.

77. The drive system of claim 76 wherein the permanent magnets include rare earth magnets.

78. The drive system of claim 73 wherein the AC motor controller further includes a media drive for receiving removable storage media.

79. The drive system of claim 73 wherein the AC motor controller further receives a brake full stroke signal and a throttle enable signal.

80. The drive system of claim 73 wherein the AC motor controller further generates a warning signal.

81. The drive system of claim 73 wherein the AC drive signal includes a 3-phase AC drive signal.

82. The drive system of claim 73 wherein the AC drive signal includes at least one of a pulse width modulation signal and a pulse frequency modulation signal.

83. The drive system of claim 73 wherein the AC motor controller determines a maximum speed of the AC motor in accordance with at least the battery voltage signal.

84. The drive system of claim 73 wherein the AC motor controller determines a maximum speed of the AC motor based on a tow switch signal and a FNR signal.

85. The drive system of claim 73 wherein the AC motor controller further generates a status signal that is communicated to a display.

86. The drive system of claim 85 wherein the status signal indicates at least one of a battery condition, an amp-hour indication, error codes, and a reverse drive condition.

87. The drive system of claim 85 wherein the display includes at least one of light emitting diodes (LEDs), a numeric display, and an alphanumeric display.

88. The drive system of claim 73 wherein the AC motor controller generates the AC drive signal when a key switch is in an on position, a FNR switch is in one of the forward and reverse positions, a tow switch is in the run position, a brake signal is indicative of 0% braking command, and a battery state of charge (SOC) is greater than a predetermined SOC.

89. The drive system of claim 73 wherein the AC motor controller slows the AC motor when the brake signal indicates greater than 0% braking command regardless of the battery voltage signal, the throttle pedal position signal, a run/tow signal, and a FNR signal.

90. The drive system of claim 73 wherein the AC motor controller determines a SOC of a battery and determines a maximum speed of the AC motor based on the SOC.

91. The drive system of claim 73 further comprising a contactor that selectively connects the AC drive signal and the AC motor, and wherein the AC motor controller further generates a PWM contactor control signal that is communicated to the contactor wherein the AC motor controller generates the contactor control signal at a first PWM duty cycle when closing the contactor and generates the contactor control signal at a second PWM duty cycle after the contactor is closed.

92. The drive system of claim 73 further comprising a brake that selectively slows the AC motor and wherein the AC motor controller further generates a brake control signal that is communicated to the brake wherein the AC motor controller generates the brake control signal at a first PWM duty cycle when applying the brake and generates the brake control signal at a second PWM duty cycle after the brake is applied.

93. The drive system of claim 92 wherein the brake includes a parking brake that is applied when the AC motor is stopped.

94. The drive system of claim 73 wherein the AC motor controller reduces the speed of the AC motor at a predetermined rate when the brake position signal indicates 0% braking command and the throttle signal indicates 0% throttle command.

95. The drive system of claim 73 wherein the AC motor controller minimizes the drive torque in forward and reverse directions when a run/tow signal indicates the utility vehicle is configured to be towed.

96. The drive system of claim 73 further comprising a rechargeable battery for providing the AC motor controller with a source of electrical energy wherein the rechargeable battery type includes one of lithium ion, nickel cadmium, nickel metal hydride, and lead-acid.

97. The drive system of claim 96 wherein the AC motor controller minimizes current flow through the rechargeable battery when the run/tow signal indicates the utility vehicle is configured to be towed.

98. The drive system of claim 96 wherein the AC motor controller recharges the rechargeable battery with energy received from the AC motor.

99. The drive system of claim 98 wherein the AC motor controller determines a percentage of the energy to provide to the rechargeable battery based on battery pack type, battery pack age, and rate of energy consumption.

100. The drive system of claim 73 further comprising a brake for slowing the utility vehicle and wherein the AC motor controller generates a brake signal for controlling the brake based on the brake position signal, a key switch signal, and a run/tow signal.

101. The drive system of claim 73 wherein the AC motor controller further includes a communication bus interface for communicating data.

102. The drive system of claim 101 wherein the data includes control data.

103. The drive system of claim 101 wherein the communication bus interface is compatible with one of a Controller Area Network (CAN), RS-232, RS-422, universal serial bus (USB), serial, parallel, wireless, Bluetooth, and optical formats.

104. The drive system of claim 103 wherein the control data includes at least one of the battery voltage signal, the throttle pedal position signal, brake pedal position signal, a key switch signal, a FNR signal, and a run/tow signal.

105. The drive system of claim 102 further comprising a battery charger that includes a second communication bus interface for communicating a battery state of charge (SOC) with the communication bus interface of the AC motor controller.

106. The drive system of claim 73 further comprising a locking differential that receives and redirects the drive torque to a pair of axles.

107. The drive system of claim 106 wherein the locking differential locks and unlocks in accordance with a differential control signal that is generated by the AC motor controller.

108. The drive system of claim 107 wherein the AC motor controller generates the differential control signal at a first PWM duty cycle when locking the locking differential and generates the differential control signal at a second PWM duty cycle after the locking differential is locked.

109. The drive system of claim 73 further comprising a plurality of wheel speed signals and wherein the AC drive signal is further based on the wheel speed signals.

110. The drive system of claim 109 wherein the AC motor controller includes at least one of an antilock braking system and a traction control system that receive the wheel speed signals and limit acceleration and deceleration of the AC motor.

111. The drive system of claim 110 wherein the traction control system limits the acceleration and deceleration based on comparing wheel speed signals associated with a respective driven wheel and a non-driven wheel.

112. The drive system of claim 73 comprising a second AC motor for providing a second drive torque wherein the AC motor controller communicates a second AC drive signal with the second AC motor and wherein the second AC drive signal is based on an operating condition of the AC motor.

113. A method of operating a drive system for a utility vehicle, comprising:

providing a drive torque; and

receiving a battery voltage signal, a throttle pedal position signal, a brake pedal position signal, and at least one of a key switch signal, a forward/neutral/reverse (FNR) signal, and a run/tow signal indicative of the utility vehicle being configured to be driven and being configured to be towed;

generating an AC drive signal in accordance with the received signals; and

converting the AC drive signal to a drive torque for propelling the utility vehicle.

114. A drive system for a utility vehicle including a plurality of wheels, comprising:

a plurality of alternating-current (AC) motors, each providing drive torque for an associated one of the wheels;

an AC motor controller that receives a battery voltage signal, a throttle pedal position signal, a brake pedal position signal, and at least one of a key switch signal, a forward/neutral/reverse (FNR) signal, and a run/tow signal indicative of the utility vehicle being configured to be driven and being configured to be towed, wherein the AC motor controller generates a plurality of AC drive signals for associated ones of the AC motors; and

wherein the AC drive signals are based on the battery voltage signal, throttle pedal position signal, brake pedal position signal, key switch signal, FNR signal, and run/tow signal.

115. A method of operating a drive system for a utility vehicle, comprising:

providing a drive torque; and

receiving a battery voltage signal, a throttle pedal position signal, a brake pedal position signal, and at least one of a key switch signal, a forward/neutral/reverse (FNR) signal, and a run/tow signal indicative of the utility vehicle being configured to be driven and being configured to be towed;

generating an AC drive signal based on the battery voltage signal, the throttle pedal position signal, the brake pedal position signal, and the at least one of the key switch signal, the FNR signal, and the run/tow signal; and

converting the AC drive signal to a drive torque for propelling the utility vehicle.