Speed sensorless observer based torque control of induction motor

A new control scheme of the torque trajectory-tracking control of an induction motor is described in the paper. The proposed approach addresses the problems of torque and flux control without the measurement of the speed of the motor, i.e. speed sensorless drive. Such a control strategy differs from the conventional field oriented control approach. First, the torque and the stator and rotor flux are controlled instead of the components of stator current i/sub sd/ and i/sub sq/. Second, a new stator and rotor flux observer based on sliding mode control and Lyapunov theory are developed. The output of the closed-loop rotor flux determines the magnitude and orientation angle of the field orientation of induction motor. Simulations and experimental tests on a 1.5 kW motor drive are provided to evaluate the consistency and the performance of the proposed control technique.