Research On Sensorless Start-up Strategies Of Permanent Magnet Synchronous Motor

In recent years,Permanent magnet synchronous motor(PMSM)has been more and more widely used.The control of PMSM usually requires the use of speed sensor to obtain the motor speed and rotor position information.However,the installation of the speed sensor will increase the mechanical complexity,increase the volume of the motor,and be limited by the adverse environment.As the speed sensorless control has made remarkable progress in recent years,this control method has been gradually applied in industry.However,without motor speed and position information,many sensorless control strategies can't start up or will produce a large current shock.Therefore,the sensorless starting method of PMSM is also one of the research emphases of sensorless control.The goal of this research is to compare,verify and develop advanced sensorless startup strategies.In this paper,the mathematical models of PMSM in different coordinate systems are deduced.On this basis,the field oriented control(FOC)method of PMSM is designed.According to the mathematical model in the rotor coordinate system and control theory,the control parameters of each controller are designed.Then maximum torque per ampere(MTPA)control and field weakening control are realized on the basis of FOC.This paper studies the speed sensorless control methods based on extended electromotive force.The basic structure of the flux observer based on extended electromotive force is designed in detail.According to the bode diagram of the system,the observation performance of the method at various speeds is predicted and verified by simulation and experiment.Then,this paper divides the startup of PMSM into static startup and flying start.Firstly,the I-F startup strategies based on the current close-loop controller is designed.This paper establishes the control model,carries out a detailed theoretical analysis and parameter design,and designs a new closed-loop controller,thus realizing a more rapid and stable method.Then,on the basis of theoretical analysis and simulation experiment,this paper makes a comparison of various flying start strategies,and analyzes the suitable application occasions of various strategies.For the theoretical analysis done above,this paper carried out the simulation analysis through MATLAB/Simulink platform,and conducted experiments on the MTPA control,speed sensorless control,I-F start control and the flying start control strategies on the experimental platform based on dSPACE DS1103,verifying the effectiveness of each control strategy and the correctness of the theoretical analysis.