Improved Continuous Non-Singular Terminal Sliding Mode Control for PMSM System

In order to solve the problem of high frequency jitter, as well as to overcome the difficulty in obtaining differentiation during the application of traditional sliding mode control (SMC) for PMSM system, this paper proposes a novel continuous non-singular terminal sliding mode (C-NTSM) control approach. Based on the mathematical model of PMSM system, the speed regulation performance is improved in the aspect of both sliding mode surface and control law. For the sliding mode surface, the power index terms concerning the system states are introduced to ensure the finite time convergence and the selection of controller parameter for the traditional SMC is removed. For the control law, a continuous control law is derived by introducing the low-pass filtering in the premise of the system states and the problem of obtaining state variable differentiation is solved. Besides, the proposed C-NTSM controller can be directly extended to the inner current loop. Finally, an experimental platform is built to demonstrate the superiority of the proposed method with over 30% improvement in vibration suppression, fast response and control accuracy.