An Improved MRAS Based Sensorless Vector Control Method for Wind Power Generator

Abstract

This paper describes an improved sensorless vector control strategy for a squirrel cage induction generator used invariable speed wind energy conversion systems (WECS). The main goal is to design a robust control algorithmimmune to generator parameter variations. In order to estimate the rotational speed of the induction generator, amodel reference adaptive system (MRAS observer) is used. It is shown that a generator parameter mismatch has agreat influence on the rotor speed estimation. In order to estimate the speed accurately, the generator statorresistance must be identified at the same time to correct the mismatched resistance value used in the observer. Theproposed rotor speed estimator with parallel stator resistance identification is first verified by computer simulation.Finally, the experiment is conducted in order to verify the obtained simulation results. It is proved that this controlscheme can enhance the efficiency of a variable speed WECS.