Patent ID: 8957537
Filing Date: 2015-02-17
Classification: F03D,F05B,Y02E

Abstract:
1. A method 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, and one or more pitch mechanisms for rotating the blades, and the method comprising a sub-nominal zone of operation for wind speeds below a nominal wind speed and a supra-nominal zone of operation for wind speeds above the nominal wind speed, wherein the first operational range extends from a cut-in wind speed to a first wind speed, and a rotor speed is kept substantially constant at a first value in the first operational range, the second operational range extends from the first wind speed to a second wind speed, and both the rotor speed and a generator torque are varied as a function of wind speed in the second operational range, the third operational range extends from the second wind speed to the nominal wind speed, and the rotor speed is kept substantially constant at a second value in the third operational range, and wherein in the second operational range, the generator torque, T, is determined in accordance with T=k·ω