Research On Predictive Current Control And Optimization Strategy Of Permanent Magnet Synchronous Motor

Permanent magnet synchronous motors have been widely used in many fields such as new energy vehicles,rail transportation,industrial servo control,naval electric propulsion,and aerospace because of its high efficiency,high power density,high torque to current ratio,and wide speed range.With the widespread application of permanent magnet synchronous motors,more and more new control strategies have been proposed.Among them,model predictive control has a simple structure and faster dynamic response speed,which has attracted the attention of experts and scholars at home and abroad.However,this control strategy also has problems such as large torque ripple,high current harmonic content,and susceptibility to changes in model parameters.In view of the above problems,this thesis conducts an in-depth study on the predictive current control of permanent magnet synchronous motor.The main research contents are as follows:Firstly,according to the structure of permanent magnet synchronous motor,the mathematical model of permanent magnet synchronous motor in rotating coordinate system is constructed with the help of coordinate transformation theory,and the single vector model predictive current control method of permanent magnet synchronous motor is obtained according to the mathematical model and the model predictive control principle.The feasibility is verified by simulation and experiment.Secondly,in order to solve the problem of large torque pulsation in single vector model predictive current control of permanent magnet synchronous motor,the concept of duty cycle is introduced,and permanent magnet synchronous motor duty cycle model predictive current control,double vector model predictive current control and discrete space vector modulation predictive current control are optimized respectively,and finally the feasibility is verified by simulation and experiment.Since the model predictive control is extremely dependent on the predictive model,and the permanent magnet synchronous motor is affected by the environmental conditions during operation,the motor-related parameters will change,resulting in a mismatch of the motor model parameters,which in turn affects the performance of the predictive control.This thesis first analyzes the influence of the mismatch of motor model parameters,and then builds a model free predictive current control system of permanent magnet synchronous motor based on nonlinear extended state observer.Finally,the feasibility is verified through simulation and experiment.There are 68 figures,3 tables,and 94 references in this thesis.