A robust sensorless SMC of PMSM based on sliding mode observer and extended Kalman filter

This paper is intended to compare and study the operation of two methods for estimating the position and speed of the rotor salient pole synchronous system in a sliding mode control motor. The first method is a sliding mode observer. The error between the measured currents and estimated currents is used to construct sliding mode surfaces so that after sliding mode happens, the estimated speed values are driven to converge to real ones exponentially. The second method consist on the estimation of the rotor flux position and rotor speed based on EKF for sensorless PMSM drives. These estimated values are feed-backed to the current loop of PMSM drive for vector control. The simulation results show the effectiveness of the extended Kalman filter are characterized by a very small estimation error for different rotational speeds (high speed, low speed) so as insensitivity to variations in load.