Speed Control of Sliding Mode Variable Structure for Permanent Magnet Synchronous Motors Based on Iterative Learning and Torque Compensation

To reduce the impact of periodic pulsating torque and non-periodic disturbances on the speed control performance of permanent magnet synchronous motors (PMSMs), a sliding mode variable structure control method incorporating iterative learning compensation and load torque observation compensation is proposed. First, iterative learning control (ILC) is designed to address periodic disturbances and suppress periodic torque ripple. A load torque observation compensator is developed to counteract non-periodic disturbances, thereby enhancing the system’s robustness against uncertain disturbances. Second, numerical simulations compare the proposed method with sliding mode control (SMC), sliding mode control with load torque observation compensation (SMC + LO), and linear active disturbance rejection control (LADRC). The simulation results demonstrate that the proposed control strategy achieves reduced torque ripple, improved system tracking, and strong robustness. Finally, physical experiments are conducted, and the results closely align with the simulations. Both simulation and experimental outcomes confirm the effectiveness of the proposed control strategy in enhancing the speed performance of permanent magnet synchronous motors.