Mutual Inductance Estimation Based Sensorless Adaptive Variance Controller for Doubly Fed Induction Generator

This article presents a novel robust adaptive speed control architecture that allows doubly fed induction generator (DFIG) to operate independently of any speed sensors or position encoders. The proposed speed sensorless control based on modified minimum variance adaptive control based speed observer makes the system robust to machine parameter variations and sensor malfunctions. The observer is formulated using a rotor current based reference adaptive system. To ensure robustness to current sensor failure, a modified adaptive rotor side converter control loop is proposed. The online identification for the adaptive control logic is based on the recursive least square estimation technique while the adaptive control law is based on an extended version of the minimum variance control algorithm. To ensure improved dynamic performance for the proposed control, a modification for the terminal voltage control loop is proposed. The reactive power reference for the vector control loop is calculated considering the rotor current component responsible for reactive power generation. The performance of the proposed control architecture is validated on a 1.5 MW DFIG modeled in MATLAB/Simulink and experimentally verified on hardware.