Speed control of variable speed wind turbine system

This paper presents the application of H-infinity controller for speed control of variable speed wind turbine system. For constant Wind speed and blade pitch angle aerodynamic torque coming from wind is constant, with the increase in demanded electrical torque the rotor speed decrease. Preferred function of the wind turbine is to keep the turbine speed close to rated speed and also the output power close to the rated. In this control method by controlling the demanded electrical torque the rotor speed is maintained constant. With the help of simulation it has been shown that at different demanded electrical torque the rotor speed is constant hence uncertainty due to demanded electrical torque is restrained by the robust controller.