A new stable MRAS-based speed and stator resistance estimators for sensorless vector control induction motor drive at low speeds

MRAS-based sensorless vector control induction motor schemes discussed in the literature suffer from pure integration problems, instability problems and sensitivity to stator resistance mismatch at low speed operation. In this paper, novel stable MRAS speed and stator resistance estimators based on current estimation have been proposed and designed. These estimators have been designed to be stable in the various operating modes, for individual and simultaneous use, following a design procedure based on linear control theory. Simulations and experimental investigations have been performed to show the stability of the proposed estimators.