Power generating system including permanent magnet generator and shunt AC regulator

• US 20030057926A1
• Filed: 09/21/2001
• Published: 03/27/2003
• Est. Priority Date: 09/21/2001
• Status: Active Grant

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: Huggett, Colin, Kalman, Gabor
• Granted Patent: US 6,838,860 B2
• Time in Patent Office: Days
• US Class Current: 322/46
• CPC Class Codes: H02J 3/1842 wherein at least one reactive element is actively controlled by a bridge converter, e.g. active filters
• CPC Class Codes: H02P 2101/30 for aircraft
• CPC Class Codes: H02P 9/02 Details of the control
• CPC Class Codes: Y02E 40/20 Active power filtering [APF]

Abstract

An electrical power distribution system includes permanent magnet generator, and an ac regulator. The ac regulator includes an inverter shunt-connected to the permanent magnet generator, and an inverter control for causing the inverter to regulate voltage at output terminals of the generator by providing reactive power (either leading or lagging) that circulates between the inverter and the generator.

Claims

1. A system comprising:

a permanent magnet generator; and

an ac regulator including an inverter shunt-connected to the permanent magnet generator, and an inverter control for causing the inverter to regulate voltage at output terminals of the generator by providing reactive power that circulates between the inverter and the generator.

2. The system of claim 1, wherein the generator is a high reactance permanent magnet generator.

3. The system of claim 1, wherein the generator includes stator windings coupled to ac terminals of the inverter, rated current of the stator windings being at least equal to short circuit current during full-speed operation of the generator.

4. The system of claim 1, wherein the reactive power is the difference between reactive power supplied by the generator and reactive power demanded by a load connected to the system.

5. The system of claim 1, wherein the inverter control operates in a synchronous reference frame with respect to voltage at an ac interface.

6. The system of claim 5, further comprising a capacitor bank coupled to the output terminals of the generator;

and wherein the inverter control operates in a d-q synchronous reference frame with respect to capacitor voltage, whereby the capacitor bank provides the ac interface.

7. The system of claim 5, wherein the inverter control includes cascaded inner and outer control loops, and space vector modulation logic, the outer loop generating a vector-based current command for the inner loop, the inner current loop generating a vector-based voltage command for the space vector modulation logic.

8. The system of claim 7, wherein the outer loop generates an amplitude component of the vector-based current command in direct proportion to voltage error at the ac interface.

9. The system of claim 7, wherein a phase angle component of the vector-based current command is a fixed value.

10. The system of claim 7, wherein a phase angle component of the vector-based current command is derived from a difference between a reference voltage command and measured dc link voltage.

11. The system of claim 7, wherein the inner loop sums a direct component of the vector-based current command with a direct component of an inverter current Park vector and PI-regulates the sum to create a direct component of the vector-based voltage command;

and wherein the inner loop sums a quadrature component of the vector-based current command with a quadrature component of the inverter current Park vector and PI-regulates the sum to create a quadrature component of the voltage command, the vectors of the inner loop being synchronous with respect to a Park vector representing voltage at the ac interface.

12. Apparatus for regulating power at an ac interface on a power distribution line of a power distribution system, the apparatus comprising:

an inverter shunt-connected to the power distribution line;

means for measuring voltage at the ac interface; and

means, responsive to measured voltage, for controlling the inverter to regulate voltage at the ac interface by providing reactive power to, and drawing reactive power from, the power distribution line.

13. A method of using an inverter to regulate power at an ac interface on a power distribution line of a power distribution system, the method comprising controlling the inverter to regulate voltage at the ac interface by providing reactive power to, and drawing reactive power from, the power distribution line.

14. The method of claim 13, wherein the reactive power is the difference between reactive power supplied by the generator and reactive power demanded by a load connected to the power distribution line.

15. The method of claim 13, wherein inverter control is performed in a synchronous reference frame with respect to voltage at the ac interface.

16.he. The method of claim 15, wherein a capacitor bank is coupled to the output terminals of the generator;

and wherein the inverter control is performed in a d-q synchronous reference frame with respect to capacitor voltage.

17. The method of claim 15, wherein the inverter control is performed by generating a vector-based current command;

using the current command to generate a vector-based voltage command; and

using the voltage command to perform space vector modulation of the inverter.

18. The method of claim 17, wherein an amplitude component of the vector-based current command is computed in direct proportion to voltage error at the ac interface.

19. The method of claim 17, wherein a phase angle component of the vector-based current command is a fixed value.

20. The method of claim 17, wherein a direct component of the vector-based current command is summed with a direct component of an inverter current Park vector, and this first sum is PI-regulated to create a direct component of the vector-based voltage command;

and wherein a quadrature component of the vector-based current command is summed with a quadrature component of the inverter current Park vector and this second sum is PI-regulated to create a quadrature component of the voltage command, the vectors being synchronous with respect to a Park vector representing voltage at the ac interface.