Compensation Control Structure Design for Permanent-Magnet Synchronous Motor Servo Drives

A closed-loop compensation control structure was designed for permanent-magnet synchronous motor (PMSM) servo drives, to improve the performance of PMSMs in performing constant-speed motion and low-speed reversal motion. PMSMs have been used extensively in various types of industrial mechanical equipment. To mitigate the adverse effects of friction and external disturbances caused by loading conditions, PMSM servo drives developed in recent years have been provided with an additional compensation control structure that can improve the motion performance of PMSMs. However, PMSMs are still significantly affected by nonlinear friction during low-speed reversal motions. Therefore, in this study, compensation control structures, i.e., a disturbance observer and compensator, a coulomb friction compensator, and a low-speed friction compensator, were designed with consideration of the friction and external disturbance characteristics of the loading conditions. Constant-speed motion and reversal-motion tests were performed on a PMSM test bench. The experimental results indicated that the rate of improvement for the root-mean-square speed error of the compensation control structure designed in this study was 46.44%, confirming the feasibility and compensation effects of the proposed method.