Speed Difference Compensation Control for PMSM Based on Extended Sliding Mode Observer

In the closed-loop speed control system of permanent magnet synchronous motor (PMSM), the conventional PI control strategy is weak in load torque disturbance resistance, which is difficult to meet the control performance requirements of the speed control system. To address this problem, it is proposed to use the extended sliding mode observer (ESMO) to observe the load torque and calculate the load torque increment, and use the load torque increment as the speed difference compensation amount to feed-forward compensate the speed difference, and then judge whether to compensate the speed difference when the given speed is changed by calculating the given speed increment, and finally, the structure of the PI speed regulator is improved by adding a limiting link and a negative feedback link to the base of the PI controller. The simulation results show that the control strategy of feed-forward compensation of speed difference effectively improves the ability of the system to resist the load disturbance. The improved PI speed regulator can effectively reduce the speed overshoot when the given speed is changed.