Precise determination of angular position of a wind turbine nacelle
A method of determining an angular position of a nacelle of a wind turbine is provided, the nacelle being rotatably mounted at an upper end of a tower, the lower end of the tower being supported by a foundation. The method includes obtaining and storing a foundation angular position corresponding to a foundation reference point, the foundation angular position being relative to true north, determining a tower angular position based on the foundation angular position and information indicative of an angular relation between foundation and tower, the tower angular position corresponding to a tower reference point, receiving an encoder signal indicative of the angular position of the nacelle, detecting that a sensor mounted to the nacelle is the encoder signal such that the indicated angular position of the nacelle corresponds to the tower angular position. Furthermore, a controller for a wind turbine, a wind turbine, and a wind farm are provided.
1 . A method of determining an angular position of a nacelle of a wind turbine, the nacelle being rotatably mounted at an upper end of a tower, a lower end of the tower being supported by a foundation, the method comprising
obtaining and storing a foundation angular position corresponding to a foundation reference point, the foundation angular position being relative to true north;
determining a tower angular position based on the foundation angular position and information indicative of an angular relation between the foundation and the tower, the tower angular position corresponding to a tower reference point;
receiving an encoder signal indicative of the angular position of the nacelle;
detecting that a sensor mounted to the nacelle is located in a vicinity of the tower reference point; and
in response to the detecting updating the encoder signal such that the indicated angular position of the nacelle corresponds to the tower angular position.
2 . The method according to claim 1 , wherein obtaining the foundation angular position comprises determining the angular position of the foundation reference point before, during, and/or after installation of the foundation.
3 . The method according to claim 1 , wherein the angular relation between the foundation and the tower is indicative of a difference in angular position between the foundation reference point and the tower reference point.
4 . The method according to claim 3 , wherein the angular relation between the foundation and the tower comprises a plurality of angular relations each of which is indicative of a difference in angular position between predetermined reference points of adjacent sections of the tower.
5 . The method according to claim 1 , wherein the encoder signal is provided by a yaw encoder.
6 . The method according to claim 1 , wherein the sensor is configured to detect a sensor activation element located at the tower reference point.
7 . The method according to claim 6 , wherein the sensor is an inductive sensor.
8 . The method according to claim 1 , wherein updating the encoder signal comprises:
determining a difference between the angular position indicated by the encoder signal and the tower angular position; and
updating the encoder signal based on the difference, such that the angular position indicated by the updated encoder signal is equal to the tower angular position.
9 . The method according to claim 8 , wherein updating the encoder signal comprises adding an offset value to the encoder signal, further wherein the offset value is based on the difference.
10 . A controller for a wind turbine, the wind turbine comprising a nacelle being rotatably mounted at an upper end of a tower, a lower end of the tower being supported by a foundation, the controller comprising:
a memory unit storing a foundation angular position corresponding to a foundation reference point, the foundation angular position being relative to true north; and
a processing unit configured to;
determine a tower angular position based on the foundation angular position and information indicative of an angular relation between the foundation and the tower, the tower angular position corresponding to a tower reference point,
receive an encoder signal indicative of the angular position of the nacelle,
detect that a sensor mounted to the nacelle is located in a vicinity of the tower reference point, and
in response to the detecting the sensor being located in the vicinity of the tower reference point, update the encoder signal such that the indicated angular position of the nacelle corresponds to the tower angular position.
11 . The wind turbine comprising a controller according to the claim 10 .
12 . A wind farm comprising:
a plurality of wind turbines according to claim 11 ; and
a wind farm controller in communication with the controller of each wind turbine.
13 . The wind farm according to claim 12 , wherein the wind farm controller is configured to apply a wake steering control algorithm.