Research On Control Strategy Of Permanent Magnet Synchronous Motor Based On Sliding Mode Control Theory

As permanent magnet synchronous motors are increasingly widely used in industry,higher requirements are put forward for their system control performance,there is an urgent need for excellent control algorithms to optimize them.The sliding mode control algorithm has a fast response speed,and is insensitive to parameters and external interference,so it has been widely used in permanent magnet synchronous motors.Aiming at the surface-mounted permanent magnet synchronous motor,this article focuses on the chattering and interference of its dual closed-loop control system,and conducts an in-depth study on the sliding mode control algorithm.In the speed control loop of the system,a sliding mode speed controller based on the improved exponential reaching law is designed,aim to solve the overshoot and chattering problems of the traditional sliding mode controller.The continuous function of the state variable and the adaptive gain term are introduced into the exponential reaching law to control the motion of the system.Aiming at the disadvantageous influence of load abrupt change and viscosity coefficient,disturbance compensation is introduced,and the observed value is estimated by the designed extended sliding mode observer.Compared with the exponential reaching law,the speed overshoot is reduced by 4%,the response time is shortened by 0.015 s,and the chattering phenomenon is eliminated.In the feedback loop of speed control,an integral sliding mode position observer based on improved exponential reaching law is designed to solve the problem of position error and chattering in traditional sliding mode observer.The observer introduces a state error integral term on the traditional sliding surface,and the improved exponential approach law is used to suppress the chattering and improve the estimation accuracy.Compared with the traditional sliding mode observer,the rotor position angle observation error is reduced by 0.05 rad,and the amplitude of buffeting range is changed from ?8 r/min to ?0.5r/min.Based on the design of the above controller and observer,the overall simulation model of the permanent magnet synchronous motor double closed-loop control system under the MATLAB/Simulink environment is built.Compared with the traditional sliding control method of disturbance compensation,when the load torque changes abruptly,the speed overshoot decreases by 1%,the amplitude of chattering changes from the original ?6 r/min to ?0.1r/min,the rotor position angle error is reduced by0.05 rad,and the tracking time is increased by 0.1s;when the reference speed changes,the speed overshoot is reduced by 0.5%,The rotor position error is reduced by 0.08 rad,and the torque response time is reduced by 0.08 s.It shows that the method in this paper can improve the anti-disturbance,stability and robustness of the permanent magnet synchronous motor system,and improve its speed regulation performance.