Low-speed performance comparison of induction motor sensorless control methods

In this paper, an induction motor model reference controller (MRC) is proposed for different sensorless schemes operating at the low speed, performance of circuit model based speed and rotor flux estimators, including speed estimator, model reference adaptive system, speed observer and extended Kalman filter are analyzed under the MRC, steady-state error and transient behavior at 1 RPM of four methods were evaluated with a real-time simulation tool. The Luenberger speed observer based method was found to be the best for low speed operation.