Research On Safety Of Brakeing Control Of Pure Electric Bus

The pure electric bus currently operating in the city has become the main force of urban ground transportation.Research on pure electric bus,brake safety is one of the most important.An important part of a pure electric bus is a regenerative braking system.Adding a motor brake can not only improve the braking safety performance of the vehicle,but also reduce the energy consumption of the vehicle,increase the driving range and prolong the service life of the mechanical brake system.The purpose of this paper is to improve the safety of vehicle braking and to improve the energy recovery rate.The method used in this paper is to establish the model of regenerative braking system in MATLAB / Simulink and develop a reasonable regenerative braking control strategy.Through the simulation,we can get the braking performance and energy recovery rate of different braking control strategies.To the data processing analysis,which verified the simulation results.The innovation of this paper is to set up a driver model based on PID controller and put forward an optimized parallel braking control strategy.The main contents of this paper include:(1)By analyzing the braking characteristics of the technical parameters of a pure electric city bus,the braking force distribution coefficient ? of the actual motor-air pressure composite braking is calculated under the requirements of ECE braking regulations.It provides a theoretical basis for the following formulation of motor regenerative braking force distribution and regenerative braking control strategy.(2)The principle of motor braking is analyzed.The restraints of the motor braking and the upper limit of the motor braking force are studied.Based on the existing research,a reasonable structure scheme of the electric compound braking and the control strategy of parallel and series regenerative braking are put forward.The vehicle braking control system modeling laid the foundation.(3)The model of regenerative braking system was established by using MATLAB / Simulink,and the vehicle dynamics model,the motor model,the battery model,the driver model and the brake control strategy model were respectively established.(4)Simulation of vehicle brake control system model.The simulation is mainly divided into two main contents.The first one is to simulate and calculate the braking performance of the vehicle and calculate the braking distance and impact degree of each braking control strategy under different initial speeds and different braking intensities.Simultaneously with the braking safety,the energy recovery rate and SOC variation of each brake control strategy under different operating conditions were simulated.(5)On the basis of theoretical analysis and simulation,the improved parallel braking control strategy in this paper is burned into the MCU of the experimental sample car and the actual Shanghai urban bus rapid cycling condition is selected for road test.The collected data are analyzed Compared with the simulation data,the reliability of the brake control model and the practicability and feasibility of the brake control strategy are verified.