An enhanced sensorless control method for PMSM in rapid accelerating operation

This paper presents an enhanced sensorless method to estimate rotor position for PMSM. The proposed method is based on the estimation of the back-EMF using a state observer. The conventional sensorless methods based on back-EMF estimation has problem of model discordance to the real motor model in electrical or mechanical dynamic state. An analysis is performed to verify how this problem deteriorates the estimation performance in the dynamic situations. Proposed method modifies state observer to match to the real motor model even in a fast accelerating situation. In order to verify feasibility of the proposed method, experimental results in a steady state and a dynamic state are presented.