This study presents a novel approach to enhance the speed control performance of the permanent magnet synchronous motor (PMSM) drive system by integrating a new sliding-mode reaching law (NSMRL) with a variable-parameter generalized super-twisting observer (VGSTO). The NSMRL is developed based on the terminal attractor concept and an adaptive method. It overcomes the slow convergence of the traditional exponential reaching law. The proposed sliding-mode controller consists of the NSMRL and an integral sliding-mode surface, achieving superior convergence dynamics. Besides, the adaptive function enhances fast transient response. The VGSTO addresses the traditional extended state observer’s issue of limited bandwidth selection due to system stiffness, offering better observing performance without a large bandwidth. The added linear and extra terms further speed up observer convergence. The introduction of variable parameters further reduces the observation error of the observer. Experiments confirm the superiority of the proposed control strategy.

To enhance the speed-control performance of a permanent magnet synchronous motor (PMSM) drive system, an improved sliding-mode anti-interference control strategy is presented. Firstly, to tackle the speed fluctuation issue caused by cogging torque (a periodic disturbance) and time-varying disturbances at low set speeds in PMSM, an improved sliding-mode control (ISMC) is proposed. It consists of a continuous adaptive fast terminal sliding-mode surface (CAFTSMS) and a new reaching law (NRL). The CAFTSMS boosts the system’s immunity to interference, while the NRL, improved via an adaptive function, enhances the fast transient response and notably reduces speed fluctuations. Secondly, a quasi-proportional resonant (QPR) controller is introduced. It suppresses specific-order system harmonics, significantly reducing the harmonic amplitude and strengthening the system’s ability to handle periodic disturbances. Finally, a cascaded extended state observer (CESO) with a special cascade structure is proposed to solve the observation-delay problem in the traditional cascade structure. Experimental results show that the proposed sliding-mode anti-disturbance control strategy performs excellently in overcoming disturbances.