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 general purpose induction machine is considered. Improved versions of both speed and stator resistance on-line 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.