Stator-current-based MRAS observer for the sensorless control of the brushless doubly-fed induction machine

Brushless doubly-fed induction machines attract much attention, but the sensorless control method have rarely discussed so far. In this paper, a sensorless control scheme of brushless doubly-fed induction machines is developed based on a simplified mathematical model. The proposed scheme is achieved by designing a model reference adaptive system observer on the basis of the control winding stator current, and a rotor speed estimator is designed by a phase locked loop. In this method, the estimated rotor speed tracks the reference value with satisfactory steady performance and a dynamic tracking response. Moreover, the estimated rotor speed is consistent with the measured value. Experimental results verify the correctness of the proposed method.