Two-degree-of-freedom proportional integral speed control of electrical drives with Kalman-filter-based speed estimation

This study proposes a speed control scheme to improve the speed control performance of the permanent magnet synchronous motor (PMSM) servo system which is equipped with an absolute optical encoder. A two-degree-of-freedom proportional integral speed controller is utilised to make a good compromise between tracking and disturbance rejection performance. Properties of the controller are analysed using the root locus method. As the controller performance is prone to be deteriorated by speed measurement noise and time delay, a novel Kalman filter is used to optimise the speed measurement process. The proposed Kalman filter modifies gain matrix based on the position residue error. By this means it improves dynamic response speed without damaging steady-state precision. Experimental researches are carried out on a 5.2 kW PMSM drive prototype and the results prove the feasibility and effectiveness of the proposed scheme.