The Study Of Control Strategy Of Power System Of Pure Electric Vehicle Equipped With Electronic Control CVT

With environment and energy issues becoming terrible day by day, vehicleswith non-emissions, low noise and other advantages attract much attention. Electriccars are the main development direction of the automobile industry in manycountries. The efficiency level of pure electric vehicle power system directlydetermines the vehicle performance, so the study of electric vehicle power controlsystem is very necessary.As a result of CVT speed ratio can be continuously changed, the drivingconditions and motor of the electric vehicles equipped with mechanical and electricalcontrol of metal belt CVT can work independently. Electric cars with electricalcontrol of metal belt type CVT can improve the electric automobile driving systemefficiency and fuel economy by adjust the CVT speed ratio of the motor at theoptimal point. Moreover, because the traditional hydraulic system is replaced by themechanical and electrical control system, mechanical and electrical control of metalbelt type CVT is not only applied in electric vehicles valuably, but also improves theefficiency of the transmission system greatly.This paper mainly researched the control of power system of electric vehicleequipped with the electrical and mechanical control of metal belt type CVT. At first,the type and performance of drive motor of electric vehicle and the structure of drivesystems were introduced based on reading a large number of literatures, then theworking principle of the electrical control of metal belt type CVT was analyzed, thespeed ratio mathematical model was established and the speed ratio control strategyof driving system was researched based on it. The author used a control strategywhich compromised economy and power. Through the analysis of the PID controlalgorithm and the compare of advantages and disadvantages of the analysis, theintegral separation PID ratio control algorithm was chosen and a method todetermine the motor optimal operation line was present. The vehicle simulationmodel equipped with the CVT was built by the Matlab/Simulink software and thesimulation analysis was done based on the model. Finally, the author designed the test scheme of the motor and its controller. The motor speed-torque characteristiccurve which would provide data for determining the best work curve of the motorand the efficiency of the motor and its controller were got by the bench test.