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1. WO2012061953 - METHOD AND SYSTEM FOR OPERATING WIND TURBINE DURING FAULT

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[ EN ]

WHAT IS CLAIMED IS:

1. A method for responding to faults in a control system in a wind turbine including a rotor coupled to at least one rotor blade, at least two pitch sensors coupled to the rotor blade, at least one pitch drive, and a controller communicatively coupled to the pitch sensors and the pitch drive, said method comprising:

determining, with the controller, that a fault has occurred in the control system;

determining, with the controller, a speed of wind in the vicinity of the wind turbine; and,

rotating the rotor blade using the pitch drive to a set point if the wind speed is greater than or equal to the maximum rated velocity of the wind turbine, the set point being an angular position of the rotor blade where the rotor blade is feathered.

2. A method in accordance with claim 1, wherein, determining with the controller, that a fault has occurred in the control system comprises determining that a communication fault has occurred in the control system.

3. A method in accordance with claim 1, wherein the rotor blade is rotated about its longitudinal axis by the pitch drive.

4. A method in accordance with claim 1 , wherein the set point is an angular position of the rotor blade where a pitch angle of the rotor blade is less than 2 degrees.

5. A method in accordance with claim 1 , wherein rotating the rotor blade with the pitch drive to a set point comprises rotating the rotor blade until one of the pitch sensors determines that the rotor blade has been rotated to the set point.

6. A method in accordance with claim 1 , further comprising applying a brake to prevent further rotation of the rotor blade once the rotor blade is rotated to the set point and releasing the brake when the controller determines that the fault in the control system is cleared.

7. A method in accordance with claim 1, wherein the controller receives communications from a wind speed sensor indicative of a speed of the wind.

8. A method for responding to faults in a control system in a wind turbine including a rotor coupled to at least one rotor blade, at least one pitch sensor coupled to the rotor blade, at least one pitch drive, and a controller communicatively coupled to the pitch sensor and the pitch drive, said method comprising:

determining, with the controller, that a fault has occurred in the control system;

determining, with the controller, a speed of wind in the vicinity of the wind turbine; and,

rotating the rotor blade using the pitch drive if the controller determines that the wind speed is less than the maximum rate velocity of the wind turbine until the pitch sensor determines that the rotor blade has been rotated to a set point.

9. A method in accordance with claim 8, wherein the rotor blade is rotated about a longitudinal axis by the pitch drive.

10. A method in accordance with claim 8, wherein determining with the controller that a fault has occurred in the control system includes determining that a communication fault has occurred in the control system.

1 1. A method in accordance with claim 8, wherein the set point is an angular position of the rotor blade where the rotor blade has a pitch angle of less than 20 degrees and greater than 2 degrees.

12. A method in accordance with claim 1 1 , wherein the angular position of the set point is such that the pitch angle is less than 15 degrees and greater than 5 degrees.

13. A method in accordance with claim 1 1 , wherein the angular position of the set point is such that the pitch angle is approximately 10 degrees.

14. A method in accordance with claim 9, wherein the longitudinal axis of the rotor blade is perpendicular to an axis about which the rotor is rotated.

15. A method in accordance with claim 13, further comprising applying a brake to prevent further rotation of the rotor blade once the rotor blade is rotated to the set point.

16. A method in accordance with claim 15, further comprising releasing the brake when the controller determines that the fault in control system is cleared.

17. A backup pitch control system for controlling pitch of at least one blade of a wind turbine during occurrence of a fault in a primary control system of the wind turbine, said backup pitch control system comprising:

a pitch drive for rotating a rotor blade about a longitudinal axis of the rotor blade;

a pitch sensor positioned to determine when the rotor blade at a set point; and,

a backup controller communicatively coupled to the pitch drive and the pitch sensor, the backup controller configured to control operation of the pitch drive when a fault occurs in the primary control system.

18. A backup pitch control system in accordance with claim 17, wherein the pitch sensor is positioned to indicate when the rotor blade has been rotated to a position such that a major surface of the blade is substantially perpendicular to a direction of wind.

19. A backup pitch control system in accordance with claim 17, wherein the pitch sensor is positioned to indicate when the rotor blade has been rotated to a position such that a major surface of the blade is oriented such that the wind strikes the major surface at an angle of less than 15 degrees and greater than 5 degrees.

20. A backup pitch control system in accordance with claim 19, further comprising a second pitch sensor positioned to indicate when the rotor blade has been rotated to a position such that the major surface of the blade is substantially perpendicular to the direction of wind.