Methods and apparatus for rotor load control in wind turbines

• US 7,095,129 B2
• Filed: 06/30/2004
• Issued: 08/22/2006
• Est. Priority Date: 06/30/2004
• Status: Active Grant

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Moroz, Emilian Mieczyslaw
• Primary Examiner(s): Waks, Joseph
• Application Number:
  US10/880,715
• Publication Number:
  US 20060001268A1
• Time in Patent Office: 783 Days
• Field of Search: 290/44, 290/55
• US Class Current: 290/44
• CPC Class Codes: F03D 7/0268 Parking or storm protection
• CPC Class Codes: F03D 7/0272 by measures acting on the electrical generator
• CPC Class Codes: H02P 2101/15 for wind-driven turbines
• CPC Class Codes: H02P 9/006 Means for protecting the generator by using control H02H7/06 takes precedence; control effected upon generator excitation circuit to reduce harmful effects of overloads or transients H02P9/10
• CPC Class Codes: Y02E 10/72 Wind turbines with rotation axis in wind direction

Abstract

A wind turbine having a rotor, at least one rotor blade, and a plurality of generators, of which a first generator is configured to provide power to an electric grid and a second generator is configured to provide power to the wind turbine during times of grid loss. The wind turbine is configured to utilize power provided by the second generator to reduce loads on the wind turbine during times of grid loss.

Claims

1. A method for reducing load on a wind turbine having a rotor with at least one rotor blade, said method comprising:

using a first generator in the wind turbine to provide electrical power to a power grid;

and said method further comprising, during grid loss conditions;

idling a rotor of the wind turbine;

using a second generator in the wind turbine to provide electricity to a pitch control system of the wind turbine; and

operating the pitch control system to reduce wind loads on the wind turbine.

2. A method in accordance with claim 1 wherein the second generator is attached to a hub of the wind turbine.

3. A method in accordance with claim 2 wherein said using a second generator in the wind turbine comprises driving the second generator using a bull gear fixed to a main bearing of the wind turbine.

4. A method in accordance with claim 1 wherein the second generator is an axial flux generator.

5. A method in accordance with claim 4 wherein the axial flux generator is fitted between a hub of the wind turbine and a nacelle of the wind turbine.

6. A method in accordance with claim 1 wherein said operating the pitch control system to reduce wind loads on the wind turbine further comprises utilizing a slave controller to command a cyclic blade control.

7. A method in accordance with claim 6 wherein the slave controller is located in a hub of the wind turbine.

8. A method in accordance with claim 1 further comprising using the second generator to generate electricity to operate a yaw brake release during grid loss conditions.

9. A method in accordance with claim 8 further comprising aligning the rotor of the wind turbine with a prevailing wind direction during grid loss conditions.

10. A method in accordance with claim 9 wherein said operating the pitch control system to reduce wind loads on the wind turbine further comprises utilizing a slave controller to command a cyclic blade control.

11. A method in accordance with claim 10 wherein the slave controller is in a hub of the wind turbine.

12. A wind turbine comprising a rotor with at least one rotor blade, a first generator, and a second generator, said wind turbine configured to:

use said first generator to provide electrical power to a power grid;

and said wind turbine further configured, during grid loss conditions, to;

idle said rotor;

use said second generator to provide electricity to a pitch control system; and

operate the pitch control system to reduce wind loads on the wind turbine.

13. A wind turbine in accordance with claim 12 wherein the second generator is attached to a hub of the wind turbine.

14. A wind turbine in accordance with claim 13 further comprising a bull gear fixed to a main bearing of the wind turbine and configured to drive said second generator.

15. A wind turbine in accordance with claim 12 wherein the second generator is an axial flux generator.

16. A wind turbine in accordance with claim 15 wherein said axial flux generator is fitted between a hub of the wind turbine and a nacelle of the wind turbine.

17. A wind turbine in accordance with claim 12 wherein to operate the pitch control system to reduce wind loads on the wind turbine, said wind turbine further comprises a slave controller configured to command a cyclic blade control.

18. A wind turbine in accordance with claim 17 wherein said slave controller is located in a hub of the wind turbine.

19. A wind turbine in accordance with claim 12 further configured to use the second generator to generate electricity to operate a yaw break release during grid loss conditions.

20. A wind turbine in accordance with claim 19 further configured to aligning the rotor of the wind turbine with a prevailing wind direction during grid loss conditions.

21. A wind turbine in accordance with claim 20 wherein to operate said pitch control system to reduce wind loads on the wind turbine, said wind turbine further comprises a slave controller configured to command a cyclic blade control.

22. A wind turbine in accordance with claim 21 wherein said slave controller is in a hub of the wind turbine.

23. A wind turbine comprising a rotor, at least one rotor blade, and a plurality of generators, wherein at least a first generator of said plurality of generators is configured to provide power to an electric grid and at least a second generator of said plurality of generators is configured to provide power to the wind turbine during times of grid loss, and wherein said wind turbine is configured to utilize power provided by said second generator to reduce loads on said wind turbine during times of grid loss.

24. A wind turbine in accordance with claim 23 wherein said power provided by said second generator is used to control pitch of said at least one rotor blade during times of grid loss.

25. A wind turbine in accordance with claim 24 wherein said power provided by said second generator is used to operate a yaw brake release during times of grid loss.

26. A method for operating a wind turbine having a rotor, at least one rotor blade, and a plurality of generators, said method comprising operating a first generator of said plurality of generators to provide power to an electric grid;

operating a second generator of said plurality of generators to provide power to the wind turbine during times of grid loss, and utilizing power provided by said second generator to reduce loads on said wind turbine during times of grid loss.