Speed sensorless control for induction motor based on state observer

In this paper, a method for estimating the rotor speed of induction motor is proposed. The proposed method is based on the state observer theory. By applying the proposed method, the induction motor control system owns the ability to estimate both the rotor speed and the stator resistance of the induction motor simultaneously. The speed sensorless controlled system based on the proposed method has been built with Simulink blocks in the Matlab platform and the corresponding simulation results demonstrate that the proposed method can operate stably in the whole range of speed with preferable estimation precision of stator resistance and rotor speed.