Design of dual extended Kalman filter for permanent magnet synchronous motor

A new observer for permanent magnet synchronous motor (PMSM) is proposed in the paper based on the technique of dual extended Kalman filter (EKF). The designed observer with the estimations of motor speed, rotor position and stator resistance is mainly used in the sensorless control of a PMSM. Currently, most observers of EKF are usually used to estimate the stator of the motor, and few observers to estimate the parameter of the motor. It is well known that the resistance and inductance of the motor windings varies after a long-running operation, which causes a reduced performance of the motor controller; even lose the effectiveness of the control algorithm of the controller. Therefore, a new observer with dual EKF is investigated to estimate the state and parameter of the PMSM at the same time, which contains two sub-observers of the state filter and the parameter filter. The proposed observer achieves a high estimation accuracy of the state and parameter of PMSM with a better steady-state performance and a fast dynamic performance. Especially, the observer achieves a good ability of robustness under the external disturbance and parameter perturbation. The performance of the proposed observer is verified by the simulation results.