Robust sensorless control of PMSG with MRAS in variable speed wind energy conversion system

In this paper, a sensorless control strategy is presented for permanent magnet synchronous generator (PMSG) in wind energy conversion system. The proposed method for rotor speed estimation is based on model reference adaptive system (MRAS), furthermore, to overcome the inability to estimate precisely due to stator resistance variation which is caused by temperature rise. Real-time stator resistance identification is also considered in the MRAS speed estimator. Estimated speed is regarded as feedback signal to H^∞ controller which meets the requirement for reducing interference of external load and generator parameters uncertainty. The proposed H^∞ controller is designed by transforming the whole system into typical mixed sensitivity problem. Simulation results demonstrate good performance in rotor speed and stator resistance estimation. Furthermore, H^∞ controller is capable of tracking rotor speed command well even though the moment of inertia of generator is changed.