Patent ID: 7659637

Claim:
A variable speed wind power generation system comprising: a wind turbine in which at least one blade is attached to a rotatable shaft; a generator having a rotor that rotates together with the shaft of the wind turbine; a power converter having an active switch for controlling electric power of the generator; blade angle change means for changing the angle of the blades according to a blade angle command value; generation power command means for generating a generation power command value based on a state quantity of the wind turbine; and generator control means for controlling the power converter in order to control the active switch; wherein the generation power command means determines a generation power command value based on a wind speed; wherein the generator control means includes means for controlling the active switch to regulate the generation power of the generator in order to change the generation power amount according to the generation power command value; wherein the generation power command means includes means for determining a blade angle from the current wind speed (U) and determining the generation power command value according to the determined blade angle; and wherein the generation power command means includes means for fixing the blade angle command value in a low wind speed range and fixing the generation power command value to a maximum output value in a high wind speed range.