Modeling And Control Of Switched Reluctance Motor Drive System For Electric Vehicles

In recent years,the continuous spread of air pollution and energy crisis has led to profound changes in the automotive industry.Because of its excellent characteristics of zero emission and high energy utilization rate,electric vehicle has quickly become the key project of competing research and development in the automobile industry.As the only power source of electric vehicle drive system,there search,and control technology of motor ontology has gradually become a research hot spot in academia and industry.As the core component of the drive system of electric vehicle,how to select the power source has become a key problem.Switched reluctance motor(SRM)is considered to be one of the best driving systems for electric vehicles because of its unique advantages such as high system efficiency,wide speed range and large output torque.Therefore,based on the four-phase 8/6-pole SRM,this paper studies the static electromagnetic field analysis and dynamic modeling methods in the single-phase and two-phase excitation mode.Firstly,this paper analyzes the working principle and magnetic pole distribution of four-phase 8/6-pole SRM and discusses the reason for the excitation overlap of SRM in single-phase and two-phase excitation mode.Firstly,in the software environment of ANSYS/Maxwell,the finite element analysis(FEM)model of the motor is established,and the static electromagnetic characteristics of the motor considering the excitation overlap are analyzed.The experimental scheme of measuring the static electromagnetic parameters of SRM by indirect method is designed,and the values of mutual inductance and torque of each phase considering the excitation overlap are calculated by numerical analysis method.The accuracy of obtaining the electromagnetic characteristics of SRM by FEM analysis method is well verified.Then,based on the general mathematical model of SRM,a new modeling method considering two-phase excitation overlap in single-phase excitation mode is proposed,and the mathematical model is derived,which adds the mutual inductance between exciting phases into the model.In the MATLAB/Simulink software,the nonlinear model of SRM drive system is established and the dynamic simulation is carried out.This paper analyzes the difference between the SRM phase current and output torque in the process of excitation overlap and the traditional model and verifies that the change of electromagnetic characteristics cannot be ignored caused by excitation overlap.Finally,based on the analysis of the electromagnetic characteristics of the motor in the two-phase excitation mode,a new mathematical model of SRM considering the excitation overlap of neighboring three phases is derived.In the MATLAB/Simulink software environment,the nonlinear modeling method and dynamic simulation of SRM are carried out.The output phase current and torque are compared with those of the traditional two-phase excitation model.The results show that the excitation overlap of the neighboring three phases is common existed in the two-phase excitation mode,and the change of the electromagnetic characteristics cannot be ignored.