Speed control for PMSM based on predictive functional control and disturbance observer

Abstract

A speed controller was designed based on predictive functional control to reduce the torque ripples of a permanent magnet synchronous motor and to increase the speed control accuracy at a steady state. To solve the problem of controller deterioration due to the load disturbance, a two loop controller was designed based on the predictive functional control and a disturbance observer. The observer was used to estimate the system disturbance and compensation current was produced to feed in the speed controller to attenuate the load disturbance. Experimental results demonstrate that the system has no overshot and the speed fluctuation is 2 r/min when the motor reaches the steady state of 600 r/min from stillness. The speed fluctuation is 5 r/min when the motor is operating at a speed of 600 r/min and a 1.6 N·m torque disturbance is added. Compared with the traditional PI controller, the proposed controller decreases the speed fluctuation by 4.2%. Simulation and experimental results show that the proposed controller can increase steady accuracy and improve anti-disturbance performance.