Optimization Design Of Electromagnetic Structure Of Switched Reluctance Motor For Electric Vehicle

With the intensification of the world’s energy crisis and environmental problems,the development and research of key technologies in the field of new energy vehicles have attracted much attention.The in-wheel driven electric vehicles(EVs),which integrate motor,transmission system,and braking system,can simplify the vehicle structure,promote transmission efficiency,and improve the convenience of chassis design.and the switched reluctance motor(SRM)with excellent driving characteristics of simple structure,high reliability,high power density,high efficiency,large starting torque,and small starting current are especially suitable for the in-wheel drive form EVs.Its related key technology research has become the focus of this field.Therefore,in order to improve the overall performance of the motor,this paper studies the optimization design of SRM electromagnetic structure for in-wheel drive EV under complex time-varying conditions.Firstly,based on the working principle of SRM,mathematical model,and finite element analysis results,the SRM control system model is established in MATLAB/Simulink.The driving cycle of the vehicle studied in this paper is determined and the dynamic model of inwheel driven EV is established based on automobile theory.Combined with the complex and time-varying load characteristics of EVs,the actual working current area characteristic constraint conditions of the SRM under the in-wheel driven mode are established.Secondly,considering the requirements of EV traction performance,ride comfort,and mileage,five indicators of average torque,torque ripple,torque density,efficiency,and electromagnetic radial force under the constraints of the actual working current area are defined to evaluate the performance of SRM;nine electromagnetic structural parameters of the motor are selected as design variables and the constraints are determined.In order to improve the performance of SRM under complex time-varying conditions,a new multiindicator synchronous optimization function is proposed,and the statistical analysis method is used to obtain five weighting coefficients of indicators by analyzing the sample data.The significant and main effects of nine electromagnetic structure parameters on the response of the five indicators and the comprehensive indicator are analyzed,and the significant structure parameters that affect the comprehensive indicator and the value of non-significant structure parameters are determined.Finally,aiming at SRM under complex time-varying conditions in this paper,after analysis of the response of electromagnetic structure parameters to indicators,BP neural network algorithm is used to train the sample data to achieve the purpose of predicting the comprehensive indicator,and particle swarm optimization algorithm(PSO)is used to optimize the four-phase 8/6 SRM and output the results.By comparing the static,dynamic,torque power and efficiency map characteristics of SRM before and after optimization,the four characteristics verify the effectiveness of the optimization strategy proposed in this paper for the SRM electromagnetic structure parameters.