Redundant field drive for an electric machine

• US 20030201756A1
• Filed: 04/24/2002
• Published: 10/30/2003
• Est. Priority Date: 04/24/2002
• Status: Active Grant

• Current Assignee: Delphi Technologies Ip Limited (BorgWarner Incorporated)
• Original Assignee: Delphi Technologies, Inc. (BorgWarner Incorporated)
• Inventors: Hocken, Lary Robert, Anderson, Stephen Wayne
• Granted Patent: US 6,750,636 B2
• Time in Patent Office: Days
• US Class Current: 322/24
• CPC Class Codes: H02P 9/14 by variation of field H02P9/08, H02P9/10 take precedence
• CPC Class Codes: H02P 9/48 Arrangements for obtaining a constant output value at varying speed of the generator, e.g. on vehicle H02P9/04 - H02P9/46 take precedence

Abstract

An electric power generating system comprising: a generator including an alternator and regulator, the regulator including a normal field control and a redundant field control with a default field command and a selector for selecting between the normal field control and the redundant field control. Further disclosed, is a method of providing excitation to an alternator, comprising: receiving a field default signal indicative of an inoperative normal field control and a normal field command responsive to the normal field control, indicative of a desired duty cycle command to a field coil of an alternator. The method further includes determining if a supply voltage is greater than a selected value and formulating a default field command; transmitting a field drive responsive to the default field command to a field coil of the alternator if the field default signal is asserted.

Claims

1. An electric power generating system comprising:

an alternator; and

a regulator, including a normal field control and a redundant field control, and a selector for selecting between said normal field control and said redundant field control, said selector selecting said redundant field control when said normal field control is not operating.

2. The system of claim 1, wherein said regulator further includes fault detection, for determining and indicating whether said normal field control is not operating.

3. The system of claim 1, wherein said regulator further includes engine off detection, for determining and indicating that said alternator is not being operated.

4. The system of claim 3, wherein said engine off detection, includes frequency measurement to establish if a phase frequency of said alternator system exceeds a selected frequency threshold.

5. The system of claim 1, wherein said redundant field control includes a comparison device for determining if a supply voltage is greater than selected value for a set-point voltage.

6. The system of claim 5, wherein said comparison device includes a comparator.

7. The system of claim 5, wherein said selected value is about 13.8 volts.

8. The system of claim 5, wherein said comparison device includes hysteresis.

9. The system of claim 1, wherein said selection apparatus comprises a circuit of logic gates configured to transmit one of a default field command and a normal field command.

10. An electric machine comprising:

an alternator;

a regulator having a normal field control and a redundant field control each being coupled to said alternator;

a means for determining and indicating whether said normal field control is not operative; and

a selector for selecting between said operational field control and said redundant field control, said selector being responsive to said means for determining.

11. The electric machine of claim 10, wherein said regulator further includes an engine off detection, for determining and indicating that said alternator is not being operated.

12. The electric machine of claim 11, wherein said engine off detection, includes a frequency measurement to establish that a phase frequency exceeds a selected frequency threshold.

13. The electric machine of claim 10, wherein said redundant field control includes a comparison device for determining if a supply voltage is greater than a selected value for a set-point voltage of said electric machine.

14. The electric machine of claim 13, wherein said comparison device includes a comparator.

15. The electric machine of claim 13, wherein said selected value is about 13.8 volts.

16. The electric machine of claim 13, wherein said comparator includes hysteresis.

17. The electric machine of claim 10, wherein said selector comprises a circuit of logic gates configured to transmit one of a default field command and a normal field command.

18. A method for providing excitation to an electric machine in an electric power generating system with an alternator and a regulator with a controller executing the method, comprising:

receiving a field default signal indicative of an inoperative normal field control;

receiving a normal field command responsive to said normal field control, indicative of a desired duty cycle command to a field coil of the alternator;

formulating a default field command responsive to a selected value for a supply voltage;

selecting and transmitting a field drive responsive to said default field command to a field coil of the alternator if said field default signal is asserted; and

wherein the regulator includes an normal field control and a redundant field control.

19. The method of claim 18, further including determining and indicating that said normal field control is inoperative and generating said field default signal.

20. The method of claim 18, further including determining and indicating that said alternator is not operative via an engine off detection, and wherein said selecting and transmitting a field drive is further responsive to said engine off detection.

21. The method of claim 20, wherein said engine off detection, includes a frequency measurement to establish that a phase frequency exceeds a selected frequency threshold.

22. The method of claim 18, wherein said determining includes comparing if a supply voltage greater than selected value for a set-point voltage.

23. The method of claim 22, wherein said comparing includes hysteresis.

24. The method of claim 22, wherein said selected value is about 13.8 volts.

25. The method of claim 18, wherein said transmitting is responsive to a selector for selecting between said normal field control and wherein said selection apparatus comprises a circuit of logic gates configured to transmit one of a default field command and a normal field command.

26. An electric machine for providing a source of electrical power, comprising:

an alternator;

a first means for determining and providing an excitation to a field coil of said alternator;

a second means for determining and providing an excitation for said field coil of said alternator, said second means providing said excitation if said first means is inoperative; and

a means for determining whether said first means is inoperative.

27. A regulator for providing excitation to an alternator in an electric power generating system, comprising:

means for receiving a field default signal indicative of an inoperative normal field control;

means for receiving a normal field control signal responsive to said normal field control, indicative of a desired duty cycle command to a field coil of the alternator;

means for formulating a default field command responsive to a selected value for a supply voltage;

means for selecting and transmitting a field drive responsive to said default field command to a field coil of the alternator if said field default signal is asserted,

wherein said regulator includes an normal field control and a redundant field control.

28. The regulator of claim 27, further including means for determining and indicating that said normal field control is inoperative and generating said field default signal.

29. The regulator of claim 27, further including means for determining and indicating that the alternator is not operative via an engine off detection, and wherein said means for selecting and transmitting a field drive is further responsive to said engine off detection.