System and method for generator phase signal monitoring and control

• US 8,432,069 B2
• Filed: 06/08/2012
• Issued: 04/30/2013
• Est. Priority Date: 07/23/2009
• Status: Active Grant

• Current Assignee: C.E. Niehoff & Co.
• Original Assignee: C.E. Niehoff & Co.
• Inventors: Patterson, Ciaran
• Primary Examiner(s): Deberadinis, Robert L.
• Application Number:
  US13/492,015
• Publication Number:
  US 20120242296A1
• Time in Patent Office: 326 Days
• Field of Search: 307/140
• US Class Current: 307/140
• CPC Class Codes: H02P 9/302 Brushless excitation
• CPC Class Codes: H02P 9/305 controlling voltage H02P9/302 takes 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

A vehicle electrical system comprises a generator and a control device coupled with the generator and operable to protect the generator from catastrophic failure while providing the electrical load in the electrical system with sufficient electrical power. The control device determines a loss of symmetry between two alternating phase signals generated by a first and second phase windings of a single or multiple stator generator. In particular, the control device determines a first and second average values of two of the two or more alternating phase signals and either limits or ceases the total electrical output current of the generator, via a generator output power controller, when the first average value differs from the second average value by a predetermined value. The control device may alternatively be configured to generate an error signal without varying the generator'"'"'s total electrical output current even in the event of a malfunction.

Claims

1. A control device for a generator, said generator comprising two or more phase windings associated with one or more stators, said two or more phase windings operative to generate two or more alternating phase signals, said control device comprising:

a processor, including a programming code operable on the processor, coupled with the two or more phase windings and a generator output power controller;

wherein said processor is configured to;

(a) measure the two or more alternating phase signals, via two or more lines;

(b) determine a first and second average values of two of the two or more alternating phase signals; and

(c) apply a control signal to the generator output power controller to at least one of limit and cease a total electrical output current of the generator, via a control line, when the first average value differs from the second average value by a predetermined value.

2. The control device of claim 1, wherein the two or more alternating phase signals comprise two or more alternating phase voltage signals and wherein each alternating phase voltage signal is measured between one end of the corresponding phase winding and one of ground or reference DC.

3. The control device of claim 1, wherein the two alternating phase signals are generated by two different phase windings associated with two different stators.

4. The control device of claim 1, wherein the generator output power controller comprises at least one of a voltage regulator, a field coil, and a semiconductor switch.

5. The control device of claim 1, wherein (b) comprises filtering the two or more alternating phase signals and calculating a first and second DC values from two of the two or more filtered alternating phase signals.

6. The control device of claim 1, wherein the processor is configured to apply a phase modulated signal to limit the total electrical output current of the generator.

7. The control device of claim 1, wherein the processor is configured to apply a step signal to cease the total electrical output current of the generator.

8. The control device of claim 1, wherein (c) comprises applying a control signal to the generator output power controller to at least one of limit and cease a total electrical output current of the generator, via the control line, when a ratio between the first and second average values is outside of a predetermined range.

9. The control device of claim 8, wherein the predetermined range is substantially between 95% to 105%.

10. The control device of claim 1, wherein the processor is further configured to generate an error signal indicative of a fault condition, via a communication line, when the first average value differs from the second average value by the predetermined value.

11. The control device of claim 1, wherein the processor is further configured to measure an output voltage of the generator, via an output-voltage line, and to vary a duty cycle of the generator output power controller, via the control line, so that the output voltage is substantially equal to a regulation voltage.

12. A method for controlling a generator, said generator comprising two or more phase windings associated with one or more stators, said two or more phase windings operative to generate two or more alternating phase signals, said method comprising:

(a) measuring the two or more alternating phase signals, via two or more lines;

(b) determining a first and second average values of two of the two or more phase signals; and

(c) applying a control signal to a generator output power controller to at least one of limit and cease a total electrical output current of the generator, via a control line, when the first average value differs from the second average value by a predetermined value.

13. The method of claim 12, wherein the two or more alternating phase signals comprise two or more alternating phase voltage signals and wherein (a) comprises measuring the two or more alternating phase voltage signals between one end of the corresponding phase winding and one of ground or reference DC.

14. The method of claim 12, wherein (b) comprises filtering the two or more alternating phase signals and calculating a first and second DC values from two of the two or more filtered alternating phase signals.

15. The method of claim 12, wherein (c) comprises applying a phase modulated signal to limit the total electrical output current of the generator.

16. The method of claim 12, wherein (c) comprises applying a step signal to cease the total electrical output current of the generator.

17. The method of claim 12, wherein (c) comprises applying a control signal to the generator output power controller to at least one of limit and cease a total electrical output current of the generator, via the control line, when a ratio between the first and second average values is outside of a predetermined range.

18. The method of claim 12, further comprising:

(d) generating an error signal indicative of a fault condition, via a communication line, when the first average value differs from the second average value by the predetermined value.

19. The method of claim 12, further comprising:

(d) measuring an output voltage of the generator, via an output-voltage line; and

(c) varying a duty cycle of the generator output power controller, via the control line, so that the output voltage is substantially equal to a regulation voltage.