System and method of over voltage control for a power system

1. A power system that powers an electric machine, comprising:

a converter operable to convert alternating current (AC) power received from the electric machine into direct current (DC) power when the electric machine is operating in a generation mode;

a high voltage direct current (HVDC) bus configured to receive DC power from the converter;

at least one component that enables operation of the power system; and

a backup power supply operable to receive a status signal corresponding to an operating condition of the component, operable to receive a signal corresponding to a detected operating voltage of the HVDC bus, and operable to communicate a signal to the power converter when both the detected operating voltage is greater than a threshold voltage and when the component is not operational.

2. The system of claim 1 wherein the power converter is operable to cause a plurality of terminals of the electric machine to be shorted together in response to the signal.

3. The system of claim 1 wherein the power converter comprises a plurality of transistor devices, and wherein the signal communicated from the backup power supply to the power converter causes an operational state of the plurality of transistor devices to be set such that the plurality of terminals of the electric machine are shorted together.

4. The system of claim 1 wherein communicating a signal to the power converter further comprises communicating a plurality of gating signals to a plurality of transistor devices such that when the transistor devices are gated, the plurality of terminals of the electric machine are shorted together.

5. The system of claim 1 wherein the component comprises:

a system controller operable to control operation of the power converter.

6. The system of claim 1 wherein the component comprises:

a housekeeping power supply operable to supply power to at least a system controller, wherein the system controller is operable to control the operation of the power converter.

7. The system of claim 6 wherein the power produced by the backup power supply is electrically isolated from the power produced by the housekeeping power supply.

8. The system of claim 1 further comprising:

a system controller operable to control operation of the power converter;

a first connection configured to communicate a test signal generated by the system controller to the backup power supply to cause a testing of the backup power supply;

said system controller being capable of initiating said test signal during continued operation of said power system; and

a second connection configured to communicate a feedback signal generated by the backup power supply to the system controller in response to the received test signal.

9. The system of claim 8 wherein the system controller is further operable to execute a protective routine in response to the feedback signal.

10. The system of claim 9 wherein executing the protective routine comprises:

prohibiting the electric power system from starting.

11. The system of claim 9 wherein executing the protective routine comprises:

alerting the operator of the electric machine.

12. The system of claim 8 further comprising:

an output interface operable to decouple the backup power supply from the power converter in response to the received test signal.

13. The system of claim 8 wherein the test signal is generated in response to the initiation of a device wherein the power system resides.

14. The system of claim 8 wherein the test signal is generated in response to an event that occurs during operation of the electrical system.

15. The system of claim 1 , further comprising:

a memory that stores at least logic to analyze the received status signal and the received voltage signal, determine when both the detected operating voltage is greater than a threshold voltage and when the component is not operational, and generate the signal to the power converter; and

a processor operable to retrieve and execute the logic.

16. A method for preventing over voltages in a power system coupled to a permanent magnet electric machine, comprising:

detecting an operating voltage on a high voltage direct current (HVDC) bus during continued operation of said power system;

determining if at least one component of the power system is operational;

communicating a signal to a power converter of the power system when the detected operating voltage is greater than a threshold voltage and when the component is not operational; and

shorting together a plurality of terminals of the electric machine.

17. The method of claim 16 , further comprising:

comparing the detected operating voltage to the threshold voltage.

18. The method of claim 16 , further comprising:

communicating a test signal to a backup power system;

testing operation of the backup power system; and

receiving a feedback signal in response to the communicated test signal, wherein the feedback signal corresponds to test results of the testing, and wherein shorting together the plurality of terminals of the electric machine is omitted at least during testing of the backup power system.

19. The method of claim 18 , further comprising:

communicating the test signal from a system controller to the backup power system; and

transmitting the feedback signal from the backup power system to the system controller.

20. The method of claim 18 , further comprising:

initiating operation of a device wherein the power system resides; and

communicating the test signal in response to the initiation of the device.

21. The method of claim 18 , further comprising:

communicating the test signal in response to an event that occurs during operation of the electrical system.

22. The method of claim 16 wherein determining if the component is operational further comprises determining if a house keeping power supply is operational such that the signal is communicated to the power converter when the detected operating voltage is greater than the threshold voltage and when the house keeping power supply is not operational.

23. The method of claim 16 wherein determining if the component is operational further comprises determining if a system controller is operational such that the signal is communicated to the power converter when the detected operating voltage is greater than the threshold voltage and when the system controller is not operational.

24. The method of claim 16 wherein determining if the component is operational further comprises:

determining if a system controller is operational; and

determining if a house keeping power supply is operational, wherein the signal is communicated to the power converter when the detected operating voltage is greater than the threshold voltage and when either of the system controller and the house keeping power supply is not operational.

25. The method of claim 24 wherein the signal is communicated to the power converter when the detected operating voltage is greater than the threshold voltage and when both of the system controller and the house keeping power supply are not operational.

26. The method of claim 16 , wherein communicating the signal to the power converter further comprises communicating a plurality of gating signals to a plurality of transistor devices such that when the transistor devices are gated, the plurality of terminals of the electric machine are shorted together.

27. A system preventing over voltages in a power system coupled to an electric machine, comprising:

means for detecting an operating voltage on a high voltage direct current (HVDC) bus;

means for determining if at least one component of the power system is operational;

means for communicating a signal to a power converter of the power system when the detected operating voltage is greater than a threshold voltage and when the component is not operational; and

means to short a plurality of terminals of the electric machine together when the signal is communicated.

28. The system of claim 27 , further comprising means for comparing the detected operating voltage to the threshold voltage.

29. The system of claim 27 wherein the means for determining if the component is operational further comprises:

means for determining if a house keeping power supply is operational wherein the signal is communicated to the power converter when the detected operating voltage is greater than the threshold voltage and when the house keeping power supply is not operational.

30. The system of claim 27 wherein the means for determining if the component is operational further comprises:

means for determining if a system controller is operational wherein the signal is communicated to the power converter when the detected operating voltage is greater than the threshold voltage and when the system controller is not operational.

31. The system of claim 27 wherein the means for determining if the component is operational further comprises:

means for determining if a system controller is operational; and

means for determining if a house keeping power supply is operational,

wherein the signal is communicated to the power converter when the detected operating voltage is greater than the threshold voltage and when either of the system controller and the house keeping power supply is not operational.

32. The system of claim 31 wherein the signal is communicated to the power converter when the detected operating voltage is greater than the threshold voltage and when both of the system controller and the house keeping power supply are not operational.

33. The method of claim 27 , further comprising:

means for communicating a test signal to the backup power system during continued operation of said power system;

means for testing operation of the backup power system; and

means for receiving a feedback signal in response to the communicated test signal, wherein the feedback signal corresponds to test results of the testing, and wherein shorting together the plurality of terminals of the electric machine is omitted at least during testing of the backup power system.

34. The method of claim 33 , further comprising:

means for communicating the test signal from a system controller to the backup power system; and

means for transmitting the feedback signal from the backup power system to the system controller.

35. The method of claim 33 , further comprising:

means for initiating operation of a device wherein the power system resides; and

means for communicating the test signal in response to the initiation of the device.

36. The method of claim 33 , further comprising:

means for communicating the test signal in response to an event that occurs during operation of the electrical system.

37. A processor-readable physical storage medium having stored thereon instructions configured to cause a processor to prevent over voltages in a power system coupled to an electric machine by performing the steps of:

determining an operating voltage on a high voltage direct current bus;

determining if at least one component of the power system is operational; and

generating a signal that is communicated to a power converter of the power system when the determined operating voltage is greater than a threshold voltage and when the component is not operational, to cause shorting together of a plurality of terminals of the electric machine.

38. The medium of claim 37 , further comprising instructions for comparing the detected operating voltage to the threshold voltage.

39. The medium of claim 37 wherein the instructions for determining if the component is operational further comprises instructions for determining if a house keeping power supply is operational such that the signal is communicated to the power converter when the detected operating voltage is greater than the threshold voltage and when the house keeping power supply is not operational.

40. The medium of claim 37 wherein the instructions for determining if the component is operational further comprises instructions for determining if a system controller is operational such that the signal is communicated to the power converter when the detected operating voltage is greater than the threshold voltage and when the system controller is not operational.

41. The medium of claim 37 wherein the instructions for determining if the component is operational further comprises:

instructions for determining if a system controller is operational; and

instructions for determining if a house keeping power supply is operational,

wherein the signal is communicated to the power converter when the detected operating voltage is greater than the threshold voltage and when either of the system controller and the house keeping power supply is not operational.

42. The medium of claim 37 wherein the instructions for determining if the component is operational further comprises:

instructions for determining if a system controller is operational; and

instructions for determining if a house keeping power supply is operational, wherein the signal is communicated to the power converter when the detected operating voltage is greater than the threshold voltage and when both of the system controller and the house keeping power supply are not operational.

43. The system of claim 1 further comprising:

a system controller operable to control operation of the power converter;

a first connection configured to communicate a test signal generated by the system controller to the backup power supply to cause a testing of the backup power supply after a steady state of operation has been reached; and

a second connection configured to communicate a feedback signal generated by the backup power supply to the system controller in response to the received test signal.

44. The method of claim 16 comprising the additional step of:

determining that said power system has reached a steady operating condition prior to detecting an operating voltage on a high voltage direct current (HVDC) bus.

45. The system of claim 27 additionally comprising a:

means for communicating a test signal to the backup power system;

means for testing operation of the backup power system after a steady operating condition has been reached; and

means for receiving a feedback signal in response to the communicated test signal, wherein the feedback signal corresponds to test results of the testing, and wherein shorting together the plurality of terminals of the electric machine is omitted at least during testing of the backup power system.