Model-free control Algorithm for PMSM With Improved Adaptive Time-varying Convergence Law and New Observer

In order to improve the response speed and anti-interference ability of the permanent magnet synchronous motor control system, this paper proposes a model-free controller based on improved adaptive exponential convergence law and double power sliding mode observer. Firstly, the sigmoid function is used instead of the sign function to make the control signal smoother and reduce the jitter; secondly, the system state variables are introduced to form an improved adaptive exponential convergence law to enhance the response speed and anti-interference ability; finally, an improved double power sliding mode observer is designed to enhance the anti-interference ability of the system and make the disturbance observation more accurate. Simulation results show that the improved controller reduces the overshoot by 0.46% compared with the traditional method, the adjustment time of speed and torque is shortened by at least 0.01s, the three-phase current recovers the stability faster when the load is added suddenly, and the speed reaches and stabilises at the target value more rapidly when the speed increases suddenly. In summary, the control strategy proposed in this paper achieves fast response, small overshooting, shortened adjustment time, and strong anti-interference ability in static state, effectively weakening the vibration phenomenon.