Research On Pmsm Control Based On Fractional Sliding Mode Speed Regulator

The servo system of the CNC machine tool is the execution component of the machine tool movement,and its performance directly determines the processing accuracy and processing efficiency,so it should have characteristics such as high tracking accuracy,fast response,and strong anti-interference ability.Due to the advantages of light weight,simple structure,small volume and loss,reliable operation and high efficiency and power factor,permanent magnet synchronous motors are widely used in AC servo systems of CNC machine tools.Despite its excellent characteristics,its system model is complex,which brings related problems such as current ripple,current coupling,parameter uncertainty,internal and external interference,and system saturation.Therefore,in the case where the existing manufacturing materials and equipment cannot be updated,the search for a high-performance control method for permanent magnet synchronous motors is the key to improving performance.This article mainly studies the control technology of permanent magnet synchronous motor from the following aspects:First of all,this paper establishes a mathematical model of permanent magnet synchronous motor,and elaborate on the basic principle of vector control and SVPWM algorithm.The model of deadbeat current predictive control(DCPC)was studied and stability analysis was carried out.Compared with the PI control of the current loop,the use of deadbeat current predictive control can improve the response speed of the current.Secondly,this article describes the general steps of sliding mode controller(SMC)design.Aiming at the problem that the PI controller adopts a PI controller with a large speed response overshoot and poor anti-interference ability,a sliding mode speed controller is designed and simulated.Compared with the PI control of the speed loop,the sliding mode control can improve the response speed and anti-interference ability of the speed loop.Finally,this paper introduces the approximation algorithm of fractional calculus.Aiming at the chattering problem of sliding mode controller,a reasonable fractional order sliding mode controller(FOSMC)is designed,which can weaken the chattering of the system when approaching the sliding mode surface.And the feedback channel introduces the fractional order sliding mode disturbance observer(Fractional Order Sliding Mode Disturbance Observer,FOSMDO),which can compensate the error of the system with the temperature and frequency changing parameters.