Research On Power Matching And Control Strategy Of Front And Rear Axle Double Motor Drive Pure Electric Bus

The increasingly strict national emission standards have urged the automobile industry to urgently upgrade its industry.The national Twelfth Five-Year Plan specializes in “technology transformation” of electric vehicles as the overall strategy,supporting traditional automotive companies to transform to new energy vehicle industry,which has driven the development of the entire electric vehicle industry chain.Since 2015,China’s new energy vehicle industrialization has steadily ranked first in the world.However,at present,the performance of domestic pure electric vehicles is limited by the driving range and the charging time of the power battery.Therefore,improving the economy has become an urgent need for pure electric vehicles.Relying on the school-enterprise cooperation project "Future Travel Platform Research",this thesis aims to design a front and rear axle double motor drive pure electric bus and improves the economy of pure electric buses.The research on powertrain parameters design and drive control strategies is conducted.The main research contents are as follows:（1）This thesis analyzes the power system configuration of the front and rear axle double motor drive pure electric bus.According to the criteria of power matching and the performance requirements of vehicle parameters,based on the calculation and analysis of vehicle dynamics,and referring to the dynamic test standards,the power system selection and preliminary parameter matching are carried out.（2）The driver’s intentions under different vehicle operating conditions are analyzed,and five types of vehicle operating modes and their state switching logic under corresponding operating conditions are designed,among which the power mode and economical mode of accelerator pedal control characteristics are designed respectively on the basis of the performance indexes of climbing degree and vehicle speed.A torque change rate control strategy is designed for the sudden change in torque due to different accelerator pedal control characteristics when the power mode and the economic mode are switched.（3）The principle of torque distribution strategy based on optimal efficiency and torque distribution strategy aiming at improving vehicle stability is analyzed.Considering the stability and economy of the whole vehicle,a torque distribution strategy is proposed to improve the comprehensive efficiency of the front and rear axle motors with the constraint of slip rate.（4）The dynamic simulation model of the whole vehicle is built on AVL Cruise,and the dynamic simulation is carried out to verify the rationality of parameter ma-tching.The driving control strategy model and torque distribution strategy model are built on Matlab / Simulink,and the simulation is carried out jointly with Cruise.The economy simulation is conducted and verifies the rationality of parameter matching results,torque control strategy and torque distribution strategy by comparison of simulation results.A real vehicle test is performed,and the data obtained from the test are compared with the simulation results,which verifies the accuracy of the matching calculation results of the dynamic parameters.In this thesis,the research method of combining mathematical analysis,model simulation and real vehicle test is used to match the parameters of the whole vehicle power system and design driving control strategy.While meeting the design objectives of the project,it provides a reasonable reference for the development of driving control strategy for front and rear axle double motor drive pure electric vehicle,and has a strong application value.