Speed sensorless vector controlled induction motor drive

This paper describes a simple and high-performance, rotor flux-oriented ind uction motor drive without a speed sensor. The rotor flux is estimated in t he stationary frame from measured terminal stator currents together with a feedback speed signal. The mechanical speed is estimated on the basis of th e stator and rotor circuit equations in the synchronously rotating referenc e frame. Moreover, an on-line identification technique of the rotor resista nce parameter has been presented for the purpose of updating the rotor flux and so the motor speed. The validity of the proposed approach has been jus tified through computer simulation. The results demonstrate that the system performance is satisfactory over a wide range of operating conditions. Als o, it has been proven that the proposed system is robust to the variations of the stator and rotor resistances.