Adaptive sliding mode observer for speed sensorless control of induction motors

This paper presents an adaptive sliding mode observer for speed sensorless field-oriented control of induction motors. The observer detects the rotor flux components in the two-phase stationary reference frame by the motor electrical equations. The motor speed is identified by an additional relation obtained by a Lyapunov function. The analytical development of the sliding observer and the speed identification algorithm is fully explained. Experimental results are presented, based on a TMS320F240 DSP controller implementation, showing the system performance with different observer gains and the influence of the motor parameters deviations.