POWER DISTRIBUTION SYSTEMS

• US 20130200691A1
• Filed: 06/06/2011
• Published: 08/08/2013
• Est. Priority Date: 06/08/2010
• Status: Active Grant

• Current Assignee: GE Energy Power Conversion Technology Limited (General Electric Company)
• Original Assignee: GE Energy Power Conversion Technology Limited (General Electric Company)
• Inventors: Crane, Allan David, Smith, Nicholas Simon, Maltby, Ralph Edwin
• Granted Patent: US 9,487,284 B2
• Time in Patent Office: Days
• US Class Current: 307/9.1
• CPC Class Codes: B60L 2200/32 Waterborne vessels
• CPC Class Codes: B63H 23/24 electric dynamo-electric machines H02K
• CPC Class Codes: B63J 3/04 from power plant other than propulsion power plant
• CPC Class Codes: H02J 2310/42 for ships or vessels
• CPC Class Codes: H02J 4/00 Circuit arrangements for mains or distribution networks not specified as ac or dc

Abstract

In a marine power distribution and propulsion system with a medium voltage distribution busbar (MVAC1) and a low voltage distribution busbar (LVAC1) then a rectifier (SC) is controlled, optionally to provide active filtering and static compensation benefits. A common power supply system incorporating ac generators (G1-G4) supplies power to the medium and low voltage distribution busbars. The rectifier (SC) is connected to the medium voltage distribution busbar (MVAC1). A controller (Co) uses feedback signals indicative of electrical quantities of the distribution voltages carried by both the medium voltage and low voltage distribution busbars (MVAC1, LVAC1) to control the rectifier (SC) to regulate electrical quantities at the ac terminals of the rectifier (SC) in order to achieve desired electrical quantities of the distribution voltage carried by the low voltage distribution busbar (LVAC1).

Claims

1. A power distribution system comprising:

first and second distribution busbars;

each carrying a respective distribution voltage;

a common power supply system supplying power to the first and second distribution busbars;

a power converter connected to the first distribution busbar the power converter having ac terminals; and

a controller that uses feedback signals indicative of electrical quantities of the distribution voltages carried by the first and second distribution busbars to control the power converter to regulate electrical quantities at the ac terminals of the power convener in order to achieve desired electrical quantities of the distribution voltage carried by the second distribution busbar.

2. The power distribution system of claim 1, wherein the power converter is operated according to as PWM strategy that is selected or varied by the controller.

3. The power distribution system of claim 1, wherein the common power supply system includes an ac generator connected to the first distribution busbar and the first distribution busbar carries an ac distribution voltage.

4. The power distribution system of claim 3, wherein the second distribution busbar carries an ac distribution voltage, and the common power supply system further includes a transformer connected between the first and second distribution busbars.

5. The power distribution system of claim 3, wherein the ac generator includes at least a pair of galvanically-isolated stator windings, a first stator winding supplying a first ac voltage being connected to the first distribution busbar, a second stator winding supplying a second ac voltage being connected to the second distribution busbar, and the second distribution busbar carries an ac or dc distribution voltage.

6. The power distribution system of claim 5, wherein the second stator winding is connected to the second distribution busbar by means of a second power converter, and the second distribution busbar carries a dc distribution voltage.

7. The power distribution system claim 3, wherein the power converter is connected between the first distribution busbar and an electrical load, the electrical load optionally including a propulsion motor.

8. The power distribution system of claim 1, wherein the common power supply system includes an ac generator the power converter is connected between the ac generator and the first distribution busbar, and the first distribution busbar carries a de distribution voltage.

9. The power distribution system of claim 8, wherein the ac generator includes at least a pair of galvanically-isolated stator windings, a first stator winding supplying a first ac voltage being connected to the first distribution busbar by means of the power converter, a second stator winding supplying a second ac voltage being connected to the second distribution busbar, and the second distribution busbar carrying an ac or dc distribution voltage.

10. The power distribution system of claim 9, wherein the second stator winding is connected to the second distribution busbar by means of a second power converter, and the second distribution busbar carries a dc distribution voltage.

11. The power distribution system of claim 7, wherein an electrical load is connected to the first distribution busbar, the electrical load optionally including a propulsion motor.

12. The power distribution system of claim 1, wherein the feedback signals include a first voltage feedback signal indicative of a voltage carried by the first distribution busbar and a second voltage feedback signal indicative of a voltage carried by the second distribution busbar.

13. The power distribution system of claim 3, wherein the feedback signals include a current feedback signal indicative of a current at the ac terminals of the ac generator.

14. The power distribution system of claim 1, wherein the power con controlled to regulate:

(i) power flow through the power converter, and (ii) power factor and/or harmonic distortion at the ac terminals of the power converter.

21. The power distribution system of claim 8, wherein the feedback signals include a current feedback signal indicative of a current at the ac terminals of the ac generator.

15. A method of controlling a power distribution system comprising:

first and second distribution busbars each carrying a respective distribution voltage, a common power supply system supplying power to the first and second distribution busbars, and a power converter connected to the first distribution busbar, the power converter having ac terminals, the method comprising the steps of;

using feedback signals indicative of electrical quantities of the distribution voltages carried by the first and second distribution busbars to control the power converter to regulate electrical quantities at the ac terminals of the power converter and/or electrical quantities of the distribution voltage carried by the second distribution busbar.

16. The method of claim 15, wherein the power converter is controlled to regulate electrical quantities at the ac terminals of the power converter and electrical quantities of the distribution voltage carried by the second distribution busbar according to a compromise.

17. The method of claim 15, wherein the power converter is controlled to regulate electrical quantities at the ac terminals of the power converter and electrical quantities of the distribution voltage carried, by the second distribution busbar according to a regulator switching, or mixing function.

18. The method of claim 15, wherein the power converter is controlled in accordance with a PWM strategy.

19. The method of claim 18, wherein the power converter is controlled by selecting or varying one or more of:

(i) the modulation depth of the PWM strategy,

(ii) the modulation angle of the PWM strategy,

(iii) the harmonic structure of the PWM strategy,

(iv) the PWM strategy to achieve a desired power factor for the power distribution system,

(v) the PMW strategy so that the power converter draws lagging VArs,

(vi) the PWM strategy to reduce harmonic distortion or achieve selective harmonic elimination (SHE) for the power distribution system, and

(vii) the PWM strategy to achieve a desired quality of power supply (QPS) for the power distribution system.

20. The method of claim 15, wherein the first distribution busbar carries a dc or ac distribution voltage and/or the second distribution busbar carries a dc or ac distribution voltage.