Research On Dynamic Test Platform Of Electric-electric Dual Energy Electric Vehicle Drive System

With the improvement of people’s travel comfort requirements,the demand for traditional fuel cars is also increasing.The widespread use of fossil fuels has produced many negative impacts on the environment and resources.However,power batteries used in electric vehicles have some disadvantages such as short cruising range,low specific power and short life.The appearance of supercapacitors can supplement the advantages of power batteries.Therefore,it is particularly vital to develop a test platform that can not only verify the energy distribution of the hybrid energy storage system of electric vehicles,but also simulate the test of the drive system of electric vehicles.This dissertation analyzes the problems existing in the existing test platform for electric vehicles.It analyzes the selection of the driving system structure and dual-power energy storage structure for electric vehicles.Four kinds of commonly used power batteries are comprehensively analyzed,and lithium iron phosphate batteries are selected,the charge-discharge characteristics and efficiency characteristics of batteries are analyzed,and the PNGV model is used for modeling and analysis of lithium iron phosphate batteries.The charge-discharge characteristics and efficiency characteristics of supercapacitors are analyzed in detail,and the first-order RC circuit model is selected to model and analyze supercapacitors.According to the indexes of power and economy of electric vehicles,the parameters of power battery,supercapacitor and driving motor are matched.To better distribute the energy of dual-power supply system,this dissertation designs a logical threshold control strategy.According to the required power and the characteristics of supercapacitors,the logic threshold parameters are set and the fuzzy control strategy is formulated.In CRUISE,the global light-duty test cycle（World Light-duty Test Cycle,WLTC）is selected to supply power to the single battery.Through the simulation of the whole vehicle model of a dual-power supply system,it is proved that the two strategies are reasonable,and the fuzzy control strategy is more energysaving than the logic threshold control strategy based on the filter function.According to the test function requirements of the platform,the overall plan of the test platform was formulated,and the four-quadrant operation principle of the dynamometer and the drive motor were in-depth analyzed,and the selection schemes of the two were determined;the sensors,data acquisition cards,signal conditioning circuits and platform communication modules needed for parameter measurement have also been independently selected.A test platform for the electric-electric dual-energy electric vehicle drive system is built.The upper computer is designed with Lab VIEW software,which can realize the functions of user login,parameter setting,real-time measurement,display control and data playback.Climbing,acceleration,braking feedback and continuous working conditions experiments were carried out on the power battery and the dual-power supply system as the power source respectively.