| 主权项 |
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, the method comprising:
in steady-state conditions following a power curve describing the operation of the wind turbine as a function of wind speed, the power curve 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, and wherein in steady-state conditions in the sub-nominal zone of operation, the blades are not pitched, and wherein the sub-nominal zone of operation comprises a first operational range, a second operational range and a third operational range, wherein
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, andthe third operational range extends from the second wind speed to the nominal wind speed, wherein the rotor speed is kept substantially constant at a second value, and the method further comprising in transient conditions in which the wind turbine cannot follow the power curve in the second operational range, changing the pitch angles of the blades. |
