Simulation Study On Control Of Motor Drive System For Electric Vehicle

With the increasingly traditional automobile ownership,the energy shortage and environmental pollution are becoming more and more serious.Based on abundant energy,high energy efficiency and less environmental pollution,the electric vehicle have been supported by the governments of its vigorously promote the research and development.Motor and its drive system as one of the core components of the vehicle,its type,performance and efficiency and control technology will directly affect the performance of the electric vehicle.Therefore,the research on the control of electric vehicle drive system has important theoretical and practical significance.In this paper,the performance and structure of different types of electric vehicles are analyzed and compared,and the pure electric vehicle is chosen as the research object because of its simple driving system.By comparing and analyzing the characteristics of different motors and driving performance,the permanent magnet synchronous motor(PMSM)is selected as the driving motor.Then,according to the target electric vehicle parameters and performance requirements,the relevant parameters of the motor and battery are selected.By the analysis of mathematical model of the permanent magnet synchronous motor,the voltage equation,the flux equation,the torque equation and motion equations of different coordinate system are given.The control method of permanent magnet synchronous motor(PMSM)is analyzed.By comparing and analyzing various control methods and the direct torque control(DTC)is used as the speed control method of permanent magnet synchronous motor(PMSM).Then,based on MATLAB/simulink simulation platform,a simulation model of permanent magnet synchronous motor based on direct torque control method was built,the effect of the speed and torque response of the permanent magnet synchronous motor is obtained.However,the traditional direct torque control has the problem of flux linkage and large torque ripple.In order to solve the above problems,this paper presents a second-order sliding mode variable structure direct torque control strategy based on super-helix algorithm.The second-order sliding mode variable structure controller with super-helix algorithm replaces the traditional direct torque control Bang bang controller,the simulation results show that the motor has a smaller flux and torque ripple,which have a good speed follow ability.Through the analysis of the working mechanism of electric vehicle driving system components,a pure electric vehicle driving system model are built in the paper,the system includes vehicle dynamics model,motor model,battery model,transmission model,wheel model.By analyzing the advantages and disadvantages of the traditional PID control and fuzzy control,the fuzzy PID control algorithm that combined with the advantages of the two control methods is adopted in the speed closed-loop control module.On this basis,based on the simulation software MATLAB/simulink platform,the vehicle simulation model of speed closed loop based on fuzzy PID control algorithm is established,and the simulation study is carried out under the UDDS operating mode.By comparing the PID control algorithm,it can be concluded that under the direct torque control strategy of Super-Twisting second-order sliding mode variable structure based on fuzzy PID control algorithm of speed loop,the vehicle and the speed and torque of the motor are both faster response performance.This paper reaches the pure electric vehicle drive system control requirements.