Research On Switched Reluctance Drive System For Electric Vehicle

Motor speed control is the core technology of electric vehicles,which directly affects the performance of electric vehicles.Switched reluctance motor(SRM)is a motor with simple structure,wide speed range and flexible control,which meets the driving requirements of electric vehicles.This paper takes a three-phase 12/8structure SRM as the research object,designs the software and hardware of the drive system,establishes the SRM nonlinear model,and proposes a parking and charging control strategy for electric vehicles driven by SRM.The main work of this paper is as follows:First of all,according to the working principle of SRM,this article designs the hardware circuits and software control programs of the SRM drive system,and builds the SRM control system: an asymmetric half-bridge power converter is selected,and the corresponding drive circuit,signal acquisition and isolation are designed.Circuit:The DSP28335 digital controller is selected to complete the initialization subroutine,liquid crystal display subroutine,timer interrupt subroutine,position capture interrupt subroutine,ADC sampling interrupt subroutine,and current chopping subroutine.Secondly,using the characteristic curve of flux linkage at key positions,a nonlinear simulation model of SRM is established.A method of using the improved Gaussian polynomial for flux linkage curve fitting is proposed.The fitting results are compared and analyzed with the fitting results of Gaussian polynomials and fifth-order polynomials.The analysis results show that the proposed nonlinear model can simulate the actual flux linkage curve better and has high accuracy.Based on the proposed Gaussian polynomial model,the flux linkage model,current model,torque model and mechanical equation model are established,and the modeling of the SRM system is improved.The accuracy of the model is verified by comparing the simulated current waveform with the experimental waveform.Finally,a parking charging control strategy for switched reluctance motors for electric vehicles is proposed.The SRM three-phase winding is used as the energy storage inductance of the charging circuit,and the charging current is distributed and storage controlled by the motor torque model and current model established above:during the charging process,the sum of the three-phase torque is zero,and the charging process is realized.Output zero torque control.Finally,the effectiveness of the control strategy is verified on the simulation platform.