Authors:-Nagalakshmi Chilukoti, P.Syam kumar
Abstract:-A sensorless control scheme is presented for induction motor with core loss and anon linear model is developed in well known (α, β) stationary reference frame, where the core is represented with a resistance in parallel with a magnetization inductance. An optimal rotor flux modulus is calculated by minimizing copper and core loss. This flux modulus is forced to be tracked by the induction motor along with a desired rotor velocity by means of sliding mode observer by using the super twisting algorithm. The rotor velocity is estimated by two methods. The first consist of a super twisting sliding mode observer for rotor fluxes with the purpose of retrieving the back-electromotive force components by means of the equivalent control method. The second method is based on a generalization of the phase – locked loop methodology. PI controller is used in both the technique. The robustness of the system is checked by varying the stator, rotor and core resistances.