Higher Order Predefined-time Sliding Mode Control for PMSM With Uncertain Disturbance

Permanent magnet synchronous motors (PMSM) offer several inherent advantages, such as higher power density, greater efficiency and reliability, more precise and rapid torque control, higher power factor, and longer bearing and insulation lifespans. As a result, they have been widely used in adjustable-speed traction motor drives. However, during operation, these motors are often subject to external load disturbances and parameter variations, which severely affect the robustness of the control system. To address this, an adaptive predefined-time disturbance observer (APTDO) is designed to track the disturbances in real-time and feed them back into the controller for disturbance compensation. Furthermore, to improve the control performance, a higher order predefined-time sliding mode controller (HO-PTSMC) is designed for the PMSM control system. Compared to traditional super-twisting sliding mode control (STSMC) methods, the field-oriented sliding mode control approach proposed in this paper significantly improves dynamic torque and speed responses and enhances the system's robustness under uncertain disturbances. The new sliding mode algorithm, being a fully continuous smooth function, effectively suppresses the chattering phenomenon inherent in traditional sliding mode algorithms, thereby significantly improving the steady-state performance of the system. Finally, simulations are conducted on the MATLAB Simulink platform, which validate the superiority of the proposed algorithm.