Consideration about problems and solutions of speed estimation method and parameter tuning for speed-sensorless vector control of induction motor drives

A classical model-based speed-sensorless field-oriented control method for a general-purpose induction machine is considered. Improved versions of both speed and stator resistance online estimators are presented with the aim of extending control capabilities down to zero speed. Only electrical stator measurements are needed, making the method suitable for general-purpose inverter applications. Online rotor resistance tuning is also included to fully compensate for thermal drift. Performance of the proposed drive is investigated by simulation and experiments.