Research On Dynamic Parameter Matching And Electro-Hydraulic Cooperative Braking Control Strategy Of Pure Electric Passenger Vehicle

At present,due to the short driving range and high cost,the market share of pure electric vehicles is not high.Compared with the major breakthroughs in battery and motor application technology,how to design the power system parameters of the vehicle to improve its power performance and economy It is an effective method to improve the driving range of pure electric vehicles without increasing the cost of the whole vehicle,and has become a motor drive A bright spot in the field of vehicle research.In this paper,the Dongfeng Yueda Kia K3 pure electric vehicle is used as the reference object,and the parameters of the main components of the target vehicle’s power system are matched and the electro-hydraulic cooperative braking control strategy is studied.The main contents are as follows:First,based on the target vehicle parameters and related performance indicators,select and calculate its powertrain system such as drive motor,power battery,main reducer,etc.;improve its power transmission structure,add automatic gearbox and continuously variable transmission,and dual motor drive.Use AVL-Cruise automotive simulation software to simulate the power performance and economy of the designed drive motor,power battery,etc.Secondly,the dynamic analysis is carried out under the braking condition of the target vehicle,the force of the front and rear wheels,the braking condition and the braking efficiency are studied,and the target nonlinear programming method is used to determine the braking force distribution of the front and rear axles of the target vehicle.The advantages and disadvantages of three typical electro-hydraulic cooperative braking control strategies are analyzed,and an electro-hydraulic cooperative braking control strategy based on braking force distribution is designed.Then,the influencing factors of the motor participating in the braking are analyzed,and the braking torque of the motor is restricted according to the working characteristics of the motor,the safety and life of the energy storage system,etc.;The transition of the mechanical friction braking mode should be gradually excessive to avoid sudden changes in vehicle speed and shorten the service life caused by overcharging of the power battery.A correction factor is added to limit the motor’s participation in the braking torque.In order to further improve the motor braking energy recovery rate,based on the fuzzy control theory,a system is designed according to the driver’s braking command P,vehicle speed V,battery state of charge SOC and battery temperature T as input variables,the motor braking ratio k For the fuzzy controller of output variable,the control strategy of electro-hydraulic cooperative braking is improved.Finally,the electro-hydraulic cooperative braking control strategy model is built in MATLAB/Simulink,and the co-simulation is carried out with AVL-Cruise automobile simulation software.effectiveness.