Sensorless vector control of induction motor drives using rotor flux observer

This paper presents a simple and robust sensorless direct rotor field-oriented control (SDRFOC) scheme of three-phase induction motor drives to replace the existing V/Hz scalar control. The SDRFOC algorithm is based on a reduced order closed-loop rotor flux observer. A comparison of the observer performance with the conventional V-I flux estimator demonstrates good transient response of the estimation scheme. The speed estimation is derived from the state equations of the induction motor in stationary reference frame. Simulation results are provided to prove the effectiveness of the proposed method.