Hybrid estimator using advanced model selection approach for sensorless control of PMSM

This paper presents sensorless PMSM control employing a combination of the extended Kalman filter (EKF) and the high-frequency injection algorithm for estimation of rotor position and speed. Both algorithms itself have limited usage. The hf injection algorithm itself is can be used in standstill and in very low speeds whilst EKF itself can be employed in higher speeds. The problem of the introduced “hybrid” estimator is a proper transition between the EKF and the hf injection strategy. In this paper, we present a new, more sophisticated technique for switching between these strategies based on model selection approach. Two different switching approaches are described and compared. Proposed estimator secures robust sensorless drive operation in full-speed range including standstill. Behaviour of the proposed sensorless control is analysed by experiments made on a developed laboratory prototype of PMSM drive of rated power 10.7kW.