A Novel Discrete Compound Integral Terminal Sliding Mode Control With Disturbance Compensation For PMSM Speed System

A novel discrete compound integral terminal sliding mode control (C-ITSMC) is proposed for permanent magnet synchronous motor (PMSM) speed system in this article. In this control scheme, the integral terminal sliding mode control (ITSMC) is first introduced to realize state convergence in finite time. Then, an extended state observer-based compensator is designed to solve the problem that sliding mode control needs large switching gain to handle disturbances. Third, a predictive control-based optimal control signal is obtained, and this optimal control signal is considered as an assistant control signal to drive the state to reach quasi-sliding mode in an optimal manner. In this way, reaching quality is improved and the tracking error band is further reduced. Finally, a compound control scheme is obtained. The major advantages of this scheme are characterized by output-based information only used, low order of controller, excellent model adaptability, and disturbance rejection ability. Experimental results show that the proposed control scheme can effectively reduce the output error and enhance the robustness of PMSM speed system.