Sensorless control of PMSG in variable speed wind energy conversion systems

A sensorless control strategy for a permanent magnet synchronous generator (PMSG) in variable speed wind energy conversion system (WECS) is proposed. The proposed method is based on recursive least square estimation (RLSE) algorithm for rotor speed estimation using an equation containing only stator flux and current. Further, rotor position information used for coordinate transformation is computed using the estimated speed. Stator flux required for speed estimation is obtained using a programmable low pass filter (PLPF). The estimated speed is used as the feedback signal for the speed control loop of the vector controlled machine side converter control system whose command speed is obtained from a wind speed sensorless maximum power point tracking (MPPT) controller. The front end converter is vector controlled in grid voltage reference frame. Simulation is carried out in order to verify the proposed algorithm.