Rotor blade control for high winds

Patent metadata

Field	Value
Publication number	US-2016305402-A1
Application number	US-201415037902-A
Country	US
Kind code	A1
Filing date	Nov 19, 2014
Priority date	Nov 21, 2013
Publication date	Oct 20, 2016
Grant date	—

Abstract

The invention relates to a control apparatus and method for controlling the rotor blades of a wind turbine, and in particular to controlling the rotor blades during an extreme wind event. An extended mode of operation of the wind turbine rotor beyond the cut-out wind speed is provided. In the extended mode of operation, the pitch of the wind turbine blades is actively controlled so that the rotor and the generator idle at a designated rotational speed. The rotational speed may be relatively high, say 15 to 20% of the nominal speed, compared with minimal speeds experienced by purely feathered wind turbine blades, and may be further controlled as a function of the incident wind speed. Output power control in the extended mode may be zero but is preferably a low, but non-zero value. The output power so produced may then be used as an auxiliary power source for controlling the wind turbine in situations where the utility grid fails.

First claim

What is claimed is:

1 . A method of operating a wind turbine generator having wind turbine blades with active pitch control, the method comprising:
determining an operating condition at the wind turbine generator indicative of an extreme wind event or an extreme loading event; when a determination of an extreme wind event or extreme loading event is made, maintaining the generator speed at a non-zero value, lower than the rated value, in a region above the cut-out wind speed (v_off); and operating one or more blade pitch actuators to control the rotation of the wind turbine blades.

2 . The method of claim 1 , wherein the operating condition is one or more of, the wind speed, the wind direction, a detection of turbulence, a load on a rotor blade, the load on the main bearing, and tilt and yaw moments.

3 . The method of claim 1 , wherein when a determination of an extreme wind event or extreme loading event is made, one or more controllers are operated to control the operation of the wind turbine, the controllers including a pitch controller, a tilt and yaw controller, active tower damping controller, and a drive train damping controller.

4 . The method of claim 1 , wherein in the region above the cut-out wind speed the generator speed is held constant with increasing wind speed.

5 . The method of claim 1 where the predetermined value for the generator speed is between 15 to 20% of the rated generator speed.

6 . The method of claim 1 where the predetermined value for the generator speed is between 10 to 25% of the rated generator speed.

7 . The method of claim 1 , wherein in the region above the cut-out wind speed the generator speed decreases continuously with increasing wind speed.

8 . The method of claim 7 , wherein in the region above the cut-out wind speed the generator is controlled so that the speed decreases discontinuously with increasing wind speed, featuring steps or jumps which omit predetermined values of the generator speed.

9 . The method of claim 1 , comprising in a region immediately below the cut-out wind speed, operating one or more blade pitch actuators and maintaining the generator speed at a predetermined value for a given wind speed, the predetermined value for the generator speed decreasing with increasing wind speed.

10 . The method of claim 1 comprising detecting a cut_out wind speed (v_off) and electrically disconnecting the wind turbine generator from the utility grid.

11 . The method of claim 10 comprising, in a region above the cut-out wind speed (v_off), controlling the generator to have a non-zero power output, and diverting the output power to provide auxiliary power for the wind turbine control systems.

12 . The method of claim 1 , comprising operating a yaw drive to angle the rotor of the wind turbine generator to face in the oncoming wind direction.

13 . The method of claim 11 , comprising detecting a yaw error and if the yaw error is greater than a threshold, setting the generator speed to zero and shutting down the wind turbine generator.

14 . A wind turbine generator comprising:
one or more wind turbine blades coupled to a generator; one or more blade pitch actuators for controlling the pitch angle of the one or more wind turbine blades; one or more sensors for detecting an operating condition at the wind turbine generator indicative of an extreme wind event or an extreme loading event; a controller for controlling the operation of the generator and the one or more pitch actuators, wherein the controller is operable to: determine an operating condition at the wind turbine generator indicative of an extreme wind event or an extreme loading event; when a detection of an extreme wind event or extreme loading event is made, maintain the generator speed at a non-zero value, lower than the rated value, in a region above the cut-out wind speed (v_off); and operate the one or more blade pitch actuators to control the rotation of the wind turbine blades.

15 . A computer program product comprising code which when executed on the processor of a wind turbine controller cause the controller to undertake any of the steps of claim 1 .

Assignees

• Vestas Wind Sys As

Inventors

• Caponetti Fabio
• Couchman Ian
• Krüger Thomas
• Zaib Ali
• Thomsen Carsten Nørlund

Classifications

• F03D7/0264 Primary

  for stopping; controlling in emergency situations (orientating out of wind F03D7/0208) · CPC title

• H02J11/00

  Circuit arrangements for providing service supply to auxiliaries of stations in which electric power is generated, distributed or converted · CPC title

• H02K7/183

  wherein the turbine is a wind turbine (adaptation of a wind turbine to an electric generator F03D9/25) · CPC title

• F03D9/255

  connected to electrical distribution networks; Arrangements therefor · CPC title

• F05B2270/3201

  "cut-off" or "shut-down" wind speed · CPC title