A new sliding mode flux and speed observer for speed sensorless control of induction machine

In this paper a new sliding mode flux and speed observer is proposed for induction machine drive systems. The error between the actual and observed currents converges to zero which guarantees the accuracy of the flux observer. The rotor speed and the rotor time constant are estimated based on the estimated stator currents and rotor flux. The estimated rotor time constant is used in slip calculation and observer structures and the estimated speed is used as feedback to the speed regulation. Computer simulation results of the speed control verify the validity of the proposed speed estimation algorithm.