Electric motor clamping system

• US 9,614,465 B2
• Filed: 07/26/2011
• Issued: 04/04/2017
• Est. Priority Date: 07/26/2011
• Status: Active Grant

• Current Assignee: Moog Incorporated
• Original Assignee: Moog Incorporated
• Inventors: Shriver, Michael H., Stevens, John W.
• Primary Examiner(s): Ip, Paul
• Application Number:
  US14/234,778
• Publication Number:
  US 20140152201A1
• Time in Patent Office: 2,079 Days
• Field of Search: 318376, 318 63, 31840002, 31840029, 318434, 187290, 187296, 244 76 R, 244111, 244195 R
• CPC Class Codes: B64C 9/323 associated with wings
• CPC Class Codes: F03D 7/0252 with aerodynamic drag devices on the blades
• CPC Class Codes: F05B 2260/507 using servos, independent actuators, etc.
• CPC Class Codes: H02P 29/025 the fault being a power interruption
• CPC Class Codes: H02P 3/08 for stopping or slowing a dc motor
• CPC Class Codes: H02P 3/12 by short-circuit or resistive braking
• CPC Class Codes: H02P 3/14 by regenerative braking
• CPC Class Codes: H02P 3/22 by short-circuit or resistive braking
• CPC Class Codes: Y02E 10/72 Wind turbines with rotation axis in wind direction

Abstract

An electric motor system having a power supply, an electric motor connected to the power supply, an object driven by the motor having a range of motion and a substantially neutral position within the range of motion, a power sensor configured to sense power from the power supply, a position sensor configured to sense position of the object in at least a portion of the range of motion, an energy storage, a controller connected to the power supply and the energy storage, wherein the controller is configured to brake the motor as a function of the position sensor, the neutral position and the power sensor.

Claims

1. An electric motor system comprising:

a power supply;

an electric motor connected to said power supply and having a braking element;

an object mechanically coupled to said electric motor and driven by said motor;

said object having a range of motion and a substantially neutral position within said range of motion;

a power sensor configured to sense power from said power supply;

a position sensor configured to sense position of said object in at least a portion of said range of motion;

an energy storage connected to said electric motor;

a controller connected to said position sensor, said power sensor and said energy storage;

said controller configured and arranged to brake said motor using said braking element and power from said energy storage based on both said sensed position of said object by said position sensor relative to said neutral position and said sensed power from said power supply by said power sensor dropping below a threshold.

2. The electric motor system set forth in claim 1, wherein said electric motor comprises at least two input terminals, said braking element comprises a switching network configured to selectively connect said terminals of said electric motor, and said controller is configured to dynamically brake said motor.

3. The electric motor system set forth in claim 2, wherein said braking element comprises a dissipation switch in series with a dissipation resistor connected to said motor, and wherein said controller is configured to operate said dissipation switch such that energy from said motor is dissipated with said dissipation resistor.

4. The electric motor system set forth in claim 1, wherein said controller is configured to regeneratively brake said motor.

5. The electric motor system set forth in claim 4, and further comprising a switching network connected to said motor, and wherein said controller is configured to operate said switching network such that energy from said motor is used to charge said energy storage when said energy storage is not fully charged.

6. The electric motor system set forth in claim 5, wherein said energy storage comprises a capacitor or a battery.

7. The electric motor system set forth in claim 5, wherein said switching network comprises six switch elements in an H bridge configuration.

8. The electric motor system set forth in claim 1, wherein said controller is configured to actively brake said motor.

9. The electric motor system set forth in claim 8, wherein said braking element comprises a brake actuator.

10. The electric motor system set forth in claim 9, and further comprising a switching network connected to said brake actuator and said energy storage, and wherein said controller is configured to operate said switching network such that energy from energy storage is used to brake said motor.

11. The electric motor system set forth in claim 10, wherein said switching network comprises six switch elements in an H bridge configuration.

12. The electric motor system set forth in claim 11, wherein said switch elements comprise IGBTs or MOSFETs.

13. The electric motor system set forth in claim 1, wherein said controller is configured to selectively actively brake, dynamically brake or regeneratively brake said motor.

14. The electric motor system set forth in claim 13, and further comprising a switching network and a dissipation resistor connected to said motor, wherein said controller is configured to operate said switching network such that energy from said motor is selectively dissipated with said dissipation resistor or used to charge said energy storage when said energy storage is not fully charged.

15. The electric motor system set forth in claim 1, and further comprising a power rectifier connected to said power supply.

16. The electric motor system set forth in claim 15, wherein said power rectifier comprises a full wave diode rectifier.

17. The electric motor system set forth in claim 1, wherein said object comprises an aircraft spoiler panel on an aircraft wing.

18. The electric motor system set forth in claim 17, wherein said neutral position is about four degrees from said aircraft wing.

19. The electric motor system set forth in claim 1, wherein said object comprises a turbine blade on a power generating turbine.

20. The electric motor system set forth in claim 19, wherein said neutral position is a feathered position.

21. The electric motor system set forth in claim 1, wherein said position sensor comprises an encoder, a resolver or a LVDT.

22. The electric motor system set forth in claim 1, wherein said power sensor comprises a voltage sensor or a FPGA validity sensor.

23. The electric motor system set forth in claim 1, wherein said power supply comprises a three phase AC power supply.

24. The electric motor system set forth in claim 1, and further comprising an output filter connected to said electric motor.

25. The electric motor system set forth in claim 24, wherein said output filter comprises a common mode filter or a differential mode filter.

26. The electric motor system set forth in claim 1, and further comprising an input filter connected to said power supply.

27. The electric motor system set forth in claim 26, wherein said input filter comprises a common mode filter or a differential mode filter.

28. The electric motor system set forth in claim 1, and further comprising a soft start switch.

29. A method of driving a system for an electric motor, said system having an external power supply input, a position sensor signal input, a switching network having switch gates, a controller, and an energy storage, comprising the steps of:

monitoring with said controller said position sensor signal input;

monitoring with said controller said external power supply input; and

operating with said controller said switch gates to absorb power from said electric motor based on both said position sensor input relative to a neutral position and said external power supply input dropping below a threshold.

30. The method set forth in claim 29, wherein said step of operating said switch gates comprises operating said switch gates to absorb power from said electric motor when said power supply input drops below a voltage threshold and said position sensor signal input is below a position threshold.

31. The method set forth in claim 29, and further comprising the step of providing a dissipation resistor connected to said motor.

32. The method set forth in claim 31, and further comprising the step of selectively directing said absorbed power to said energy storage or said dissipation resistor as a function of whether said energy storage is fully charged.

33. The method set forth in claim 29, and further comprising the step of using power from said energy storage to actively brake said electric motor as a function of said position sensor input and said external power supply input.

34. The method set forth in claim 33, wherein said step of using power from said energy storage to actively brake said electric motor comprises actively braking said electric motor when a rate of change of said position sensor input signal is below a speed threshold, said power supply input drops below a voltage threshold, and said position sensor signal input is below a position threshold.

35. The method set forth in claim 34, wherein said step of operating said switch gates comprises operating said switch gates to absorb power from said electric motor when a rate of change of said position sensor input signal is above a speed threshold, said power supply input drops below a voltage threshold, and said position sensor signal input is below a position threshold.

36. The method set forth in claim 35, and further comprising the step of providing a dissipation resistor connected to said motor.

37. The method set forth in claim 36, and further comprising the step of selectively directing said absorbed power to said energy storage or said dissipation resistor as a function of whether said energy storage is fully charged.

38. The method set forth in claim 29, wherein said local energy storage comprises a capacitor or a battery.

39. The method set forth in claim 29, and further comprising the step of providing a power rectifier connected to said power supply input, and converting an AC voltage on said power supply input into a DC voltage.

40. The method set forth in claim 39, wherein said power rectifier is a full wave diode rectifier.

41. The method set forth in claim 29, and further comprising the step of providing a soft start switch.

42. The method set forth in claim 29, wherein said position sensor signal input is configured to connect to an encoder, resolver or LVDT.

43. The method set forth in claim 29, wherein said electric motor is configured to connect to an aircraft wing spoiler actuator.

44. The method set forth in claim 29, wherein said electric motor is configured to connect to a power generating turbine blade pitch control actuator.

45. The method set forth in claim 29, wherein said external power supply input is configured for a three phase AC power source.

46. The method set forth in claim 29, and further comprising the step of filtering a signal coming in on said external power supply input or filtering a signal going to said electric motor.

47. The method set forth in claim 29, and further comprising the step of providing a brake actuator.

48. A driver for an electric motor comprising:

an external power supply input;

a power sensor having an output and configured to monitor said external power supply input;

a position sensor having an output;

an AC to DC power rectifier;

a switching network having switch gates and configured to convert a DC power from said power rectifier to an AC source for said electric motor;

a control connected to said switch gates and configured to monitor said power sensor output and said position sensor output and configured to operate said switch gates;

a local energy storage for temporarily supplying power to said switching network;

wherein said control is configured to operate said switch gates such that a recovered power is drawn from said electric motor based on both said power sensor output dropping below a threshold and said position sensor output relative to a neutral position.

49. The driver set forth in claim 48, and further comprising a dissipation resistor connected to said electric motor.

50. The driver set forth in claim 49, wherein said control is configured to direct power from said electric motor to said dissipation resistor.

51. The driver set forth in claim 49, wherein said control is configured to operate said switching network such that energy from said motor is selectively directed to said dissipation resistor or said local energy storage when said local energy storage is not fully charged.

52. The driver set forth in claim 48, wherein said control is configured to direct power from said electric motor to said local energy storage.

53. The driver set forth in claim 48, and further comprising a brake actuator connected to said local energy storage.

54. The driver set forth in claim 53, wherein said control is configured to operate said switching network such that energy from said local energy storage is directed out said brake actuator.

55. The driver set forth in claim 48, wherein said switching network comprises six switch elements in an H bridge configuration.

56. The driver set forth in claim 55, wherein said switch elements comprise IGBTs or MOSFETs.

57. The driver set forth in claim 48, wherein said control is configured to selectively actively brake, dynamically brake or regeneratively brake said electric motor.

58. The driver set forth in claim 48, wherein said power rectifier comprises a full wave diode rectifier.

59. The driver set forth in claim 48, and further comprising an output filter connected to said switching network.

60. The electric motor system set forth in claim 59, wherein said output filter comprises a common mode filter or a differential mode filter connected to said AC to DC power rectifier.

61. The driver set forth in claim 48, and further comprising an input filter connected to said AC to DC power rectifier.

62. The driver set forth in claim 61, wherein said input filter comprises a common mode filter or a differential mode filter.

63. The driver set forth in claim 48, and further comprising a soft start switch.