Voltage Regulation to Reduce Ripple in a Power Generation System

• US 20090167255A1
• Filed: 12/26/2007
• Published: 07/02/2009
• Est. Priority Date: 12/26/2007
• Status: Active Grant

• Current Assignee: Hamilton Sundstrand Corporation (Rtx Corporation), Pratt & Whitney Canada Corporation (Rtx Corporation)
• Original Assignee: Hamilton Sundstrand Corporation (Rtx Corporation), Pratt & Whitney Canada Corporation (Rtx Corporation)
• Inventors: Rozman, Gregory I., Dooley, Kevin A.
• Granted Patent: US 7,859,230 B2
• Time in Patent Office: Days
• US Class Current: 322/25
• CPC Class Codes: H02M 1/14 Arrangements for reducing ripples from dc input or output
• CPC Class Codes: H02M 7/30 by dynamic converters
• CPC Class Codes: H02P 2101/10 for water-driven turbines
• CPC Class Codes: H02P 9/102 for limiting effects of transients
• CPC Class Codes: H02P 9/14 by variation of field H02P9/08, H02P9/10 take precedence
• 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

Methods and systems are disclosed for reducing alternating current ripples in direct current electrical power generation systems with one or more regulated permanent magnet machines. Ripple suppression is achieved, in one aspect, by modulating the control current of a regulated permanent magnet machine.

Claims

1. A ripple suppression circuit for regulating direct current (DC) power converted from alternating current (AC) power produced by a regulated permanent magnet generator (PMG) having a control winding, the DC power having voltage or current ripple, the ripple suppression circuit comprising:

a synchronization unit for deriving a synchronization signal;

a synchronous compensator for determining, using the synchronization signal, a compensation signal to at least partly suppress the voltage or current ripple; and

a voltage regulator control unit for producing a current modulation signal for modulating a control current in the control winding in response to the compensation signal to adjust the AC power and hence also to regulate the DC power.

2. The ripple suppression circuit of claim 1, wherein the synchronization unit derives the synchronization signal phase voltages of the stator of the PMG or a position of the rotor of the PMG.

3. The ripple suppression circuit of claim 1, further comprising a voltage or current transducer for respectively measuring the voltage or current ripple in a stationary reference frame.

4. The ripple suppression circuit of claim 1, wherein the synchronous compensator integrates harmonic components of the voltage or current ripple in a synchronous reference frame for determining harmonic components of the compensation signal in a synchronous reference frame and further wherein the voltage regulator control unit produces the current modulation signal in response to the harmonic components of the compensation signal.

5. The ripple suppression circuit of claim 4, wherein the synchronous compensator transforms the harmonic components of the compensation signal into a stationary reference frame.

6. The ripple suppression circuit of claim 1, further comprising a voltage regulator for producing, under control of the current modulation signal, the control current for forwarding to the control winding of the regulated PMG.

7. A ripple suppression circuit for regulating direct current (DC) power converted from alternating current (AC) power produced by a regulated permanent magnet generator (PMG) having a control winding, the DC power having voltage or current ripple, the ripple suppression circuit comprising:

means for deriving a synchronization signal;

means for determining, using the synchronization signal, a compensation signal in a synchronous reference frame to at least partly suppress the voltage or current ripple; and

means for producing a current modulation signal for modulating current in the control winding in response to the compensation signal in order to adjust the alternating current power and hence also to regulate the DC power.

8. A method for regulating direct current (DC) power converted from alternating current (AC) power produced by a regulated permanent magnet generator (PMG) having a control winding, the DC power having voltage or current ripple, the method comprising:

deriving a synchronization signal;

determining, using the synchronization signal, a compensation signal in a synchronous reference frame to at least partly suppress the voltage or current ripple; and

producing a current modulation signal for modulating a control current in the control winding in response to the compensation signal in order to adjust the alternating current power and hence also to regulate the DC power.

9. The method of claim 8, wherein the deriving comprises deriving the synchronization signal from phase voltages of the stator of the PMG or a position of the rotor of the PMG.

10. The method of claim 8, further comprising measuring the voltage or current ripple in a stationary reference frame.

11. The method of claim 8, further comprising integrating harmonic components of the voltage or current ripple in a synchronous reference frame for determining harmonic components of the compensation signal in a synchronous reference frame and further comprising producing the control current modulation signal in response to the harmonic components of the compensation signal.

12. The method of claim 11, further comprising transforming the harmonic components of the compensation signal into a stationary reference frame.

13. The method of claim 8, further comprising producing, under control of the current modulation signal, the current for forwarding to the control winding of the regulated PMG.

14. A direct current electric generator comprising:

a regulated permanent magnet generator (PMG) drivingly connected to a prime mover to produce alternating current power, the regulated PMG comprising control windings through which a control current has an effect on the alternating current power;

a rectifier arranged to convert the alternating current power into direct current power having a voltage or current ripple; and

a ripple suppression circuit for regulating the direct current power, the ripple suppression circuit comprising;

a synchronization unit for deriving a synchronization signal;

a synchronous compensator for determining, using the synchronization signal, a compensation signal to at least partly suppress the voltage or current ripple; and

a voltage regulator control unit for producing a current modulation signal for modulating current in the control winding in response to the compensation signal in order to adjust the alternating current power and hence also to regulate the DC power.