A control arrangement of a wind turbine includes a watchdog including a reset module and a trigger module, wherein the watchdog reset module is configured to perform an internal reset when a sign-of-life signal is received from a remote communication system within a predetermined time limit, and wherein the watchdog trigger module is configured to issue a watchdog trigger when the predetermined time limit is exceeded; a sensor arrangement including a number of sensors configured to observe local parameters and to report local sensor data; and a wind turbine controller that initiates a local control sequence in response to the watchdog trigger, which local control sequence is configured to switch between a first mode of operation and a second mode of operation on the basis of the local sensor data. A method of operating a wind turbine is further provided.

A controller for a wind turbine including a rotor and a nacelle arranged on a tower is provided, the tower having a fundamental frequency close to or below a rated rotational frequency of the rotor. The controller includes a rotor speed control module including a first linear time invariant control system adapted to generate a first pitch control signal based on a rotor speed error signal, a tower damping module including a second linear time invariant control system adapted to generate a second pitch control signal based on a nacelle acceleration signal, and an output module adapted to output a pitch control signal based on the first pitch control signal and the second pitch control signal. Furthermore, a wind turbine and a method of controlling a wind turbine is provided.

A method for compensating the output power of wind turbine generator set includes acquiring the average values of the first ambient temperature of environments where the wind turbine generator set is located in various periods; collecting the output power of the wind turbine generator set at the end time of various periods; compensating the set output power collected at the end time of current period according to difference value between the average value of the first ambient temperature in the current period and that in the previous period so as to guarantee the stability of the set output power if the average value of the first ambient temperature in the current period and the average value of the first ambient temperature in the previous period both are higher than a preset temperature threshold value.

A wind power generation system has a windmill, a lift improvement device, a power generator, a storage, and a controller. The windmill rotates when receiving an airflow. The lift improvement device has a capability of operating and halting, the lift improvement device increases a lift force to a blade of the windmill when operating. The power generator generates power by rotation of the windmill and a torque is generated in a direction suppressing rotation of the windmill. The storage stores a plurality of characteristic maps indicating characteristics of the torques of the power generator in relation to rotation speeds of the power generator. The controller controls a power generation amount of the power generator by switching and using the plurality of characteristic maps of the storage in correspondence with a state of operating or halting of the lift improvement device.

A method and corresponding arrangement are provided for determining pitch angle adjustment signals for adjusting a pitch angle of a rotor blade connected to a rotation shaft of a wind turbine. The method includes obtaining a first maximal speed signal indicative of a first desired maximal rotational speed of the rotation shaft. The method also includes deriving a first pitch angle adjustment signal based on the first maximal speed signal. The method further includes obtaining a second maximal speed signal indicative of a second desired maximal rotational speed of the rotation shaft different from the first desired maximal rotational speed of the rotation shaft. Further, the method includes deriving a second pitch angle adjustment signal based on the second maximal speed signal. The second pitch angle adjustment signal is different from the first pitch angle adjustment signal.

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.

Provided are a control method and apparatus for load reduction of a wind turbine. The control method for load reduction includes: determining a representative blade root load value of a wind turbine; determining an additional pitch rate value based on the representative blade root load value; determining a pitch rate control value based on a given pitch rate value and the additional pitch rate value: and applying the pitch rate control value to each blade of the wind turbine, to control each blade of the wind turbine to perform a pitch action.

A method for protecting a wind turbine from an extreme change in wind direction includes receiving a wind direction and/or a wind speed at the wind turbine. When a change in the wind direction or the wind speed exceeds a predetermined threshold, the method includes determining a margin to stall and/or zero lift of the at least one rotor blade of the wind turbine as a function of an angle of attack or change in the angle of attack at a blade span location of at least one rotor blade of the wind turbine. The method also includes implementing a corrective action for the wind turbine (without shutting down the wind turbine) when the margin to stall and/or zero lift exceeds a predetermined value so as to avoid stall and/or negative lift on the at least one rotor blade during operation of the wind turbine.

The invention relates to a method of identifying a wind distribution pattern over a rotor plane and a wind turbine thereof. At least one operating parameter of the wind turbine and a rotational position of the rotor are measured over a time period. A first wind turbine blade passing signal is extracted from the measured operating parameter and a second wind turbine blade passing signal is generated from the rotational position. The first and second wind turbine blade passing signals are then analysed to determine the characteristics of the actual wind turbine blade passing signal in the rotor plane. These characteristics are afterwards compared to the characteristics of a plurality of known wind distribution patterns, and a unique relationship between the characteristics of the wind turbine blade passing signal and the wind distribution pattern is used to identify a distinctive wind distribution pattern.

The invention is a method for controlling and/or monitoring a wind turbine 1 equipped with a LIDAR sensor 2. Control and/or monitoring provides an estimation of the wind speed at the rotor obtained an estimator and a LIDAR sensor 2. The estimator of the wind speed at the rotor is constructed from a representation of the wind, a model of the LIDAR sensor and a model of wind propagation.