A method for controlling pitching of at least one rotor blade of a wind turbine includes receiving, via one or more position localization sensors, position data relating to the at least one rotor blade of the wind turbine. Further, the method includes determining, via a controller, a blade deflection signal of the at least one rotor blade based on the position data. Moreover, the method includes determining, via a computer-implemented model stored in the controller, a pitch command for the at least one rotor blade as a function of the blade deflection signal and an azimuth angle of the at least one rotor blade.

According to an embodiment, a method of controlling a temperature of a blade includes generating a first power production curve based on current weather conditions and generating a second power production curve based on future weather conditions. The method also includes, in response to determining that the second power production curve reduces a net power production loss of the blade more than the first power production curve, adjusting a heating cycle of the blade based on the second power production curve rather than the first power production curve.

The present invention relates to control of a wind turbine in a stop process in response to a rotor stop signal. The rotor stop process comprises the steps of prior to receipt of the rotor stop signal, generating a stored pitch angle signal by storing pitch angle signals for at least a fraction of a rotor revolution, and determining at least one periodic component of the stored signal. The rotor blades of the wind turbine are controlled towards a feathering position using a pitch control signal containing the at least one periodic component.

The present invention relates to control of a wind turbine in a stop process where a stop controller is used to pitch the blades at a number of pre-set pitch rates including a first pitch rate and a second pitch rate. The stop controller is arranged to access desired pitch angles of the stopping process and add an envelope band to the desired pitch angles. In the stop process, pitching at a selected pitch rate among the number of pre-set pitch rates is performed, and the pitch rate is changed according to criteria to keep the pitch value within the envelope band.

The invention is about a method for controlling a wind turbine with a variable rotor area. The wind turbine comprises a rotor with one or more rotor blades which are arranged hinged at an adjustable pivot angle, where the variable rotor area depends on the pivot angle, and where the pivot angle is adjustable dependent on a variable pivot force provided by a pivot actuator. The method comprises determination of a maximal pivot force based on the input operational parameter which relate to an actual load or a predicted load of the wind turbine, determining a desired pivot force based on a desired operational performance of the wind turbine, and determining a pivot force set-point to be applied to the pivot actuator based on the desired pivot force so that the pivot force set-point is equal to or below the maximal pivot force.

A method of controlling pitch of individual blades in a wind turbine is described, together with a suitable controller. Wind speed is determined as a function of azimuthal angle. Wind speed is then predicted for individual blades over a prediction horizon using this determination of wind speed as a function of azimuthal angle. The predicted wind speed for each individual blade is used in a performance function, which is optimized to control individual blade pitches.

The present invention relates to a method of controlling a wind turbine comprising a tower supporting a rotor comprising a plurality of pitch-adjustable rotor blades. The method includes obtaining a movement signal indicative of a lateral movement of the tower; determining a pitch modulation signal, based on the movement signal, for actuating a rotor blade to produce a desired horizontal force component to counteract the lateral movement of the tower; determining a radial force component acting on a rotor blade; determining a phase offset parameter for the rotor blade based on the radial force component; and, transforming the pitch modulation signal into a pitch reference offset signal for the rotor blade based on the phase offset parameter.

There is provided a method (40) of correcting blade pitch in a wind turbine (10) having a tower (12) and a plurality of rotor blades (18). The method (40) comprises: receiving (410) sensor output data from one or more wind turbine sensors (141), the sensor output data including data indicative of excitation of the tower (12) for a plurality of different pitch angles of a particular one of the blades (18); determining (420) a corrected pitch reference of the particular blade (18), the corrected pitch reference corresponding to a minimum tower excitation based on the received sensor output data; and, sending (430) the corrected pitch reference to a pitch actuator system (24) of the particular blade (18).

The present disclosure is directed to a system and method for assessing farm-level performance of a wind farm. The method includes operating the wind farm in a first operational mode and identifying one or more pairs of wind turbines having wake interaction. The method also includes generating a pairwise dataset for the wind turbines pairs. Further, the method includes generating a first wake model based on the pairwise dataset and predicting a first farm-level performance parameter based on the first wake model. The method also includes operating the wind farm in a second operational mode and collecting operational data during the second operational mode. Moreover, the method includes predicting a first farm-level performance parameter for the second operational mode using the first wake model and the operational data from the second operational mode. The method further includes determining a second farm-level performance parameter during the second operational mode. Thus, the method includes determining a difference in the farm-level performance of the wind farm as a function of the first and second farm-level performance parameters.

A method of operating a wind turbine is provided. The wind turbine comprises a turbine rotor with at least two blades, each blade having a variable pitch angle. The method comprises determining mechanical loads on the blades, determining an asymmetric load moment experienced by the turbine rotor based on the mechanical loads on the blades, determining high order harmonics from the asymmetric load moment, and determining an individual pitch control signal for each of the blades for varying the pitch angle of each blade to compensate for the asymmetric load moment. The individual pitch control signal for each blade is determined at least based on the high order harmonics.