A High-Performance Control System of PMSM Based on Load Torque Observer

A load torque observer based on Kalman filter is proposed which can observe the load torque, rotor speed and position of permanent magnet synchronous motors (PMSM) with only very low accuracy mechanical position sensor. With the observed rotor position and speed instead of the values measured directly from mechanical sensor, control performance can be greatly improved and the cost of the system can be decreased. Observed load torque can be used as feedforward compensation which can eliminate the effects of load torque changes. Then, a state space position controller is formed which can get a better position control performance than traditional method.