A simple induction motor speed estimator: Performance evaluation from low speed to field weakening region

A sensorless induction motor drive, with decoupled control of electromagnetic torque and of stator flux, has been developed. The performance of the proposed speed estimator has been deeply investigated through both simulation and experimental analyses, in an extended speed range, from near standstill to the field weakening region. Several experimental results, which have been obtained developing a 7.5 kW induction motor drive, are presented and show the good accuracy attained by the estimation process, despite the simple structure and the easy implementation of the proposed observer.