Robust sliding mode control of induction motor (IM) drive without speed sensor

Speed sensorless control of IM drive depends on the estimation of internal state variables which are based on measured terminal voltages and currents. In high performance systems the estimation of the magnitude and spatial orientation of rotor flux relies on dynamic model of IM and different estimation schemes differ with respect to robustness and accuracy. In this paper a modified adaptive sliding observer for robust estimation of rotor flux and motor speed of the variable structure system controlled IM drive is discussed. All the theoretical issues are verified by simulation and experimental results.