Application of EKF to parameter and state estimation of PMSM drive

The authors describe the application of the extended Kalman filter theory to the parameter and state estimation of a permanent-magnet synchronous motor drive for a microprocessor based adaptive speed control in the presence of a variable load. The electronically commutated permanent magnet synchronous motor is controlled according to the principle of field orientation. An adaptive torque/speed cascade control is used to improve the performance of the system which has constrained armature current and unknown load inertia. The parameters of the controllers of the two feedback loops and that of the smoothing filter are adjusted when the changes in the load parameters have been tracked down by the estimation algorithm. The proposed estimator and the adaptive control scheme have been simulated, the results show that they perform well