Study On PMSM Speed Regulation System For Pure Electric Vehicle Based On Weak Magnetic Control

Due to the continuous depletion of oil resources and environmental pollution caused by vehicle exhaust emissions,the limitations of traditional fuel vehicles are becoming more and more obvious.Because of its clean and pollution-free,high energy conversion efficiency,electric vehicles have attracted human attention and become the first choice of public transportation.As the preferred motor of electric vehicle drive system,permanent magnet synchronous motor(PMSM)has some disadvantages,such as slow response speed,poor antiinterference ability and so on,which will greatly reduce the driver’s driving experience and even bring security risks.Based on the weak magnetic control strategy,this paper mainly studies the PMSM speed control system for electric vehicles.Firstly,the rotor structure of PMSM is classified,and the dynamic mathematical model of PMSM is established in d-q coordinate system,including voltage matrix equation,flux equation,torque equation and motion equation.The technical principle and implementation of SVPWM,the principle and existing problems of traditional vector control are analyzed.This paper describes the control strategy of flux weakening,and analyzes the advantages and disadvantages of the two traditional control strategies of flux weakening based on leading angle and voltage closed-loop feedback.In order to improve the robustness of the system response speed and reduce the dependence of the control system on the motor parameters,the flux weakening control strategy based on the leading angle is finally determined.In view of the problems of current oscillation,large torque ripple and DC-AC current coupling existing in the control strategy based on lead angle,an improved control strategy based on lead angle is formed,and the stator current trajectory is analyzed.Secondly,based on Matlab/ Simulink modeling,simulation analysis is made on the improved leading angle control strategy proposed at base speed and base speed respectively,the results show that the dynamic performance of the motor has been significantly improved compared with the traditional weak magnetic control strategy;based on the construction of vehicle test platform based on cruise,the joint simulation platform of Matlab and cruise is constructed,which is respectively under acceleration condition and slope climber The simulation results show that the PMSM for pure electric vehicle under the control of the improved weak magnetic control strategy has good dynamic performance under the specific conditionsFinally,the PMSM speed regulation experiment platform is built,and the hardware selection and software design are carried out respectively.The effectiveness of the improved control strategy is verified by experiments.The experimental results show that the response speed of PMSM is fast,the current oscillation is reduced,and the response speed and robustness of the system are improved effectively.