Wind turbine generator system

A wind turbine generator system equipped with a synchronous generator connected to the shaft of a windmill, a converter connected to the stator winding of the synchronous generator, and an inverter connected to the converter and also to an electric power system, in which the variable-frequency power generated by the synchronous generator is converted into direct current power by the converter and then the direct-current power is converted into fixed-frequency alternating current power by the inverter comprising:

• a rotation speed detector that detects the rotation speed of the synchronous generator;
• a current detector that detects the current through the stator of the synchronous generator;
• a computing unit that converts the three-phase amperage detected by the current detector into active component and reactive component;
• a current controller that controls the active component and reactive component and outputs a voltage command;
• a filter that receives the rotation speed detected by the rotation speed detector and then extracts and outputs a specified frequency component;
• a phase gain regulator that receives the output signal of the filter and then regulates and outputs phase and gain;
• and
• an adder that adds the signal outputted from the phase gain regulator to the active component of the current command sent to the current controller.