Practical Sliding Mode Observer‐Based Adaptive Super‐Twisting Sliding Mode Control for PMSMs With Disturbance Attenuation

ABSTRACT During the operation of scraper conveyors, the permanent magnet synchronous motor (PMSM) is susceptible to sudden external load disturbances, which can severely compromise system stability. To address this issue, this paper proposes an adaptive super‐twisting sliding mode control (ASSMC) scheme incorporating a practical sliding mode observer (PSMO) for PMSM drive systems. Firstly, a PSMO is designed by introducing a fractional power term to mitigate observer chattering. This observer is employed to estimate and compensate for the impact of sudden load disturbances on the control system. Secondly, a novel adaptive super‐twisting reaching law (ASRL) is proposed. By dynamically adjusting the control gains through real‐time comparison between the absolute value of the sliding variable and a preset precision threshold, the ASRL eliminates the prior dependence on disturbance upper bounds, thereby effectively enhancing control performance under abrupt load changes. Thirdly, based on the PSMO and ASRL, together with an integral terminal sliding surface, a composite control strategy ASSMC + PSMO is then formulated. Finally, the performance of the proposed control strategy was implemented and evaluated in MATLAB/Simulink. Furthermore, an experimental test platform was established to perform comparative tests under three distinct operational scenarios: Case 1 (long‐term experiment), Case 2 (transient experiment), and Case 3 (sudden load application experiment). Both simulation and experimental results demonstrate that the proposed ASSMC + PSMO scheme outperforms the PI controller, the conventional SMC and the ASMC + SMO. Specifically, compared to these benchmark schemes, the steady‐state peak tracking error was reduced by 38.8%, 37.56%, and 1.01%, respectively, in simulations. In Case 1, the reductions were 66.2%, 8.82%, and 7.05%; in Case 2, they were 36.73%, 25.43%, and 7.57%; and in Case 3, they were 2.93%, 14.27%, and 12.03% respectively.