Research On Vector Control Of Permanent Magnet Synchronous Motor Based On Sliding Mode Variable Structure

As one of the core of the numerical control system,the performance of the permanent magnet synchronous servo system affects the processing quality of the CNC machine tool.The permanent magnet synchronous motor is a complex control system with strong coupling,multivariable and nonlinear characteristics.It is susceptible to internal parameter perturbation and external disturbance during the motion.Conventionally,permanent magnet synchronous motors generally adopt PI control.PI control belongs to linear control and has poor robustness.Therefore,the servo control for permanent magnet synchronous motors is not effective.Based on this,the sliding mode variable structure control is applied to the motor servo control.It is proved by experiments that the control method has strong robustness and good control effect.The main research contents of this paper are as follows:1.Combines the research status of domestic and foreign control strategies,compares and demonstrates the vector control as the overall control scheme of the motor,and discusses the principle of space vector pulse width modulation algorithm(SVPWM)in detail.Finally,the permanent magnet synchronous motor is built in Matlab/Simulink.Simulation model.2.Based on the analysis of the basic principle of sliding mode variable structure,the rate and accuracy of sliding mode motion approach are fully balanced.Through the comparative analysis of several approach laws,the sliding mode variable structure controller is designed based on the exponential approach law.Using the time and absolute error integral evaluation function(ITAE)as the optimization rule,the initial value of the sliding mode parameters of the sliding mode variable structure controller is determined by genetic algorithm.3.Aiming at the chattering problem in variable structure control,this paper analyzes the exponential approach law and obtains the key sliding mode parameter that affects thechattering size.Furthermore,the fuzzy control is used to optimize it in real time,and a fuzzy variable structure controller(Fuzzy-SMC)is designed for this purpose.The fuzzy control real-time optimization makes the approach speed have self-adjusting ability,and the system is also improved while suppressing chattering.The response speed enhances robustness.Finally,three models based on traditional PI,SMC and Fuzzy-SMC are built in Matlab/Simulink for simulation comparison.The simulation results show that the control effect of Fuzzy-SMC is better than that of traditional PI and SMC.4.Based on the above theory,the experimental platform with STM32 as the control core is built,and the software design is completed.The experimental results show that the fuzzy-SMC designed in this paper is more robust and the system response time is better than the traditional PI and SMC.Shorter.