Research On Application Of Sliding Mode Variable Structure Control In AC Servo System

With the progress of the times,AC servo system with permanent magnet synchronous motor is widely used in many areas.In many methods of PMSM control,sliding mode variable structure control is widely used in PMSM because it has many advantages of good robustness,high control precision and simple realization.In this paper,the application of sliding mode variable structure control in PMSM is further analyzed and studied.Firstly,the mathematical model of PMSM servo system is established.Then,the characteristics of PMSM servo system are analyzed.Finally,the traditional sliding mode variable structure control is improved in order to improve the control performance of the PMSM servo system.The control strategy is proposed,which combines the integral sliding mode variable structure control with the nonlinear saturation function defined by the two parabola,to achieve the purpose of weakening the system chattering;fast terminal sliding mode variable structure control is applied to improve the convergence speed of the speed servo system and Anti-reset Windup technology is used to eliminate the windup phenomenon in the system;a hybrid approach law based on terminal attractor and exponent is applied to improve the positioning accuracy of PMSM position servo system.All controllers are proved to be stable by the Lyapunov stability theorem.At last the numerical simulation experiment of the system is carried out by Matlab/Simulink and programming,and the effectiveness and feasibility of the improved sliding mode variable structure control method are proved.