Abstract: Methods of operating a variable speed wind turbine as a function of a wind speed, the wind turbine having a rotor with a plurality of blades, a generator having a rated output power, and one or more pitch mechanisms for rotating the blades around their longitudinal axis, and a system for varying a torque of the generator. The methods comprise a sub-nominal zone of operation for wind speeds below a nominal wind speed and a supra-nominal zone of operation for wind speeds at or above the nominal wind speed, wherein at wind speeds at or near the nominal wind speed, the generator is allowed to generate more than its rated output power for a limited period of time. Also disclosed are wind turbines and wind farms adapted to perform these methods.

Abstract: The present invention provides a method of operating a wind turbine having a rotor with a plurality of blades, a system for determining one or more loads on the wind turbine, a historical register of data on the wind turbine operation, and a control system for controlling one or more operational parameters of the wind turbine. The method comprises determining the loads on the wind turbine, and storing the determined loads on the wind turbine in the historical register. The method further comprises obtaining, from the historical register, a characteristic indicative of the loads on the wind turbine accumulated over time, and determining one or more wind thrust limits depending on the obtained characteristic indicative of the loads accumulated over time. One or more operational parameters of the wind turbine are controlled to keep the wind thrust on the wind turbine within the determined wind thrust limits.

Abstract: Method of operating a variable speed wind turbine as a function of wind speed are disclosed, the wind turbine having a rotor with a plurality of blades, a generator, pitch mechanisms for rotating the blades around their longitudinal axes, and a system for varying a torque of the generator. The method comprises at a first moment in time estimating representative future wind speed values from the first moment in time up to a second moment in time, the second moment in time being equal to the first moment in time plus a predetermined finite period of time, and using a control strategy to optimize a cost function indicative of an energy output of the wind turbine based on the estimated representative future wind speed values by controlling the torque of the generator and the pitch angles of the blades. Wind turbines suitable for such methods are also disclosed.

Abstract: Methods of operating a variable speed wind turbine as a function of a wind speed, the wind turbine having a rotor with a plurality of blades, a generator having a rated output power, and one or more pitch mechanisms for rotating the blades around their longitudinal axis, and a system for varying a torque of the generator. The methods comprise a sub-nominal zone of operation for wind speeds below a nominal wind speed and a supra-nominal zone of operation for wind speeds at or above the nominal wind speed, wherein at wind speeds at or near the nominal wind speed, the generator is allowed to generate more than its rated output power for a limited period of time. Also disclosed are wind turbines and wind farms adapted to perform these methods.

Abstract: A method of operating a wind turbine having a rotor with a plurality of blades, and one or more pitch mechanisms for rotating the blades including a sub-nominal zone of operation and a supra-nominal zone of operation for wind speeds above the nominal wind speed wherein the sub-nominal zone of operation includes a first, a second and a third operational range. The first operational range extends from a cut-in wind speed to a first wind speed, wherein the rotor speed is kept substantially constant at a first value. The second operational range extends from the first wind speed to a second wind speed, wherein both the rotor speed and generator torque are varied as a function of wind speed.

Abstract: The present invention provides a method of operating a wind turbine having a rotor with a plurality of blades, a system for determining one or more loads on the wind turbine, a historical register of data on the wind turbine operation, and a control system for controlling one or more operational parameters of the wind turbine. The method comprises determining the loads on the wind turbine, and storing the determined loads on the wind turbine in the historical register. The method further comprises obtaining, from the historical register, a characteristic indicative of the loads on the wind turbine accumulated over time, and determining one or more wind thrust limits depending on the obtained characteristic indicative of the loads accumulated over time. One or more operational parameters of the wind turbine are controlled to keep the wind thrust on the wind turbine within the determined wind thrust limits.

Abstract: A method of operating a wind turbine having a rotor with a plurality of blades, and one or more pitch mechanisms for rotating the blades is disclosed. The method comprises a sub-nominal zone of operation and a supra-nominal zone of operation for wind speeds above the nominal wind speed. The sub-nominal zone of operation comprises a first, a second and a third operational range. The first operational range extends from a cut-in wind speed to a first wind speed, wherein the rotor speed is kept substantially constant at a first value. The second operational range extends from the first wind speed to a second wind speed, wherein both the rotor speed and generator torque are varied as a function of wind speed.