Research On The Control Strategy And Test Bench Of The Pure Electric Vehicle Power System

The pure electric vehicle is an important strategic target of new energy vehicles,its power system is the main factor affecting the performance and fuel economy of the vehicle.The energy consumption has a direct impact on battery state and driving range of electric vehicles.At the same time,the regenerative braking control strategy is the key control strategy of electric vehicle power system.Based on the research of a precursor type of pure electric vehicle power system,the following three problems are studied: 1.Establishing the simulation model of the pure electric vehicle power system and studying the regenerative braking control strategy with different adhesion coefficients;2.In order to improve the efficiency of energy recovery and braking stability of electric vehicles,it designs a kind of improved-type control strategy of power system with simple technology and strong operability;3.Seting up the the electric vehicle power system tester,which includes the performance test of the motor,the battery and regenerative braking.Designing the tester monitoring system.Specific researches are as follows:(1)This paper summarizes and analyzes the basic structure and principle of pure electric vehicle power system.According to the simulation and test requirements,the mathematical model of the motor is established,and the characteristic test of the power battery is carried out.The mathematical model of the battery is established based on the LPV theory.The concept of characteristic value of pavement state is introduced,and the wheel model is established.(2)Studying the influence factors of regenerative braking ability of pure electric vehicles.Designing a control strategy,with ECE R13 regulations as the criterion,which can be used in high and low road adhesion coefficient.And considering the actual motor's generating capacity and battery's charging capacity,to determine the maximum regenerative power supplied by the motor.(3)Using ADVISOR software and on basis of a pure electric vehicle model,the paper improves and embeds the control strategy,improves the simulation model of the motor,battery and wheels.It compares with the original control strategy,and the simulation results and the origina l simulation results are analyzed.The braking energy recovery efficiency of the pure electric vehicle is calculated under the improved control strategy.(4)The system of the regenerative braking tester is established,and the vehicle inertia,driving resistance and braking force are simulated by the relevant components.To complete the establishment of tester,a plurality of batteries are connected in series to form an energy storage system,combined with DC/DC converter.And the monitoring system is designed by LabVIEW.The results show that the improved control strategy can effectively improve the braking energy recovery efficiency under the premise of ensuring the braking performance.Compared with the original control strategy,the effective braking energy recovery efficiency is respectively increased by 5.47% and 5.7% at UDDS and ECE driving cycle.And the regenerative braking tester is established,which can be used to test motor performance and regenerative braking performance,and it can monitor the state of the motor and battery.