A MRLS with RMRAC applied to Sensorless Speed Control without Time Rotor Dependence

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, a direct estimation of the rotor flux estimation is used, so the proposed scheme can be applied without shaft encoder and independent of the rotor resistance. Experimental results are given to show the effectiveness of the proposed controller