A modified reaching phase sliding mode controller for a speed sensorless inducting motor drive using feedback linearization theory



A speed sensorless induction motor drive (IMD) with a modified reaching phase sliding mode controller is introduced. The rotor flux is estimated first, with a simplified rotor flux observer in the rotor reference frame and the feedback linearization theory is used to decouple the dynamic of the motor torque and rotor flux amplitude. Then, a modified reaching sliding mode controller is designed to control the speed of the IMD so that the chattering effects associated with the classical sliding mode speed controllers is eliminated and a fast transient response is also achieved. In addition, a Luenberger speed observer is designed to estimate the IMD speed from the measured terminal voltages and currents. The effectiveness of the proposed approach is demonstrated by a digital simulation study.