High Performance PMSM Sensorless Control with Load Torque Observation

This paper proposes a new state observer based on extended Kalman filter (EKF) for the sensorless control of permanent magnet synchronous motors (PMSM). The observer can obtain exact rotor speed and position with which sensorless control can be achieved. Load torque is also observed and used as the feed-forward compensation to improve the system performance during load torque changes. In this system, the initial rotor position is not necessary for the start up. Based on the observed variables, a state space position control controller is built up. Simulations and experiments have been done to verify the performances of the system.