A RMRAC applied to speed control of an induction motor without shaft encoder

This paper proposes a robust model reference adaptive controller (RMRAC) for a speed sensorless induction motor drive. A modified recursive least squares (MRLS) is proposed to avoid the use of mechanical sensors. The MRLS is obtained modifying a recursive least squares (RLS) using a sigma-modification. The obtained controller is used to assure performance in a wide speed range, including low and zero speed conditions. Moreover, the RMRAC control law reduces the time project and compensating mechanical parametric uncertainties. Experimental results are given to show the effectiveness of the proposed controller.