Sliding-mode observer based rotor resistance updating method for indirect vector controlled induction motor

An adaptive sliding-mode observer is proposed in this paper to update the rotor resistance in indirect field oriented controlled induction motor drives. Although the observer is implemented in stationary reference frame, the design and theory analysis are made in the rotor-field oriented reference frame. Through coordinate transformation, the essence of the sliding- mode manifold and the theory foundation of the observer are feasible to be exposed clearly. As shown through simulation and experiment, the proposed observer not only can work well at different rotor speeds, but also is robust to other parameters. By integrating this adaptive scheme into the vector controlled motor drives, the performance can be improved.