A speed control for a PMSM using finite-time feedback control and disturbance compensation

The speed-regulation problem for a permanent-magnet synchronous motor (PMSM) servo system is studied in this paper. In order to improve the disturbance rejection property of the PMSM, a novel composite controller for the speed-loop is presented. First, an extended state observer (ESO) is introduced to estimate the disturbances of the system. The estimated value is used in the feed-forward compensation design. Second, a continuous feedback-based finite-time control technique is employed for the feedback design. The composite speed controller can be considered as a composition of finite-time proportional feedback plus feed-forward compensation based on ESO (FTP + ESO). Two standard proportional—integral (PI) controllers are employed for two current loops. The closed-loop system of the speed error can be regarded as a first-order finite-time control system with bounded disturbances. Rigorous analysis shows that the proposed scheme can enhance the disturbance rejection property of the closed-loop system. Simulation and experimental comparisons with two other control methods, ie the composite control method with proportional feedback plus feed-forward compensation based on ESO (P + ESO), and the PI control method, are given to verify the effectiveness of the proposed method.