Research On Regenerative Braking Of Pure Electric Vehicle With Double Electric Mechanism

With the rapid development of industry,environmental pollution and energy depletion have become the two major problem humanity is facing with.Therefore,the automobile industry is facing with great changes.New energy vehicles have been developed rapidly these days,especially for battery electric vehicles.However,the driving range has become a key issue restricting the development of pure electric vehicles.Starting with the new configuration and regenerative braking,it is of great theoretical significance and practical value to carry out the research on the key technologies of pure electric vehicles aiming at increasing energy efficiency and increasing the mileage.The main research work and innovation are as follows:(1)A new dual motor drive system for pure electric vehicles is proposed.Firstly,the paper has made a detailed introduction to the structure scheme of the transmission system configuration,on the basis,this paper divided working model for the dual motor configuration of pure electric vehicle,and did the dynamic analysis of different driving modes and switching process between modes.Single motor driven pure electric vehicle always being set large power,in order to meet the power requirements,which cause the loading rate is low in most of the time,so the efficiency is low,however,the new configuration proposed in this paper not only through the double motor drive can reduce the capacity of a single motor,improving single motor load rate,can also change gear when the time is appropriate,in order to improve the dynamic performance and fuel economy,compared with the traditional single motor fixed ratio structure can greatly improve the utilization rate of energy.(2)Developed the shift control strategy without power interruption.Due to the double motor configuration proposed in this paper,the phenomenon of power interruption will occur when the transmission chain is broken.Therefore,developed corresponding non power interruption shift control strategy according to different driving modes,ensured that the braking force of the motor does not exit suddenly during the braking process,so as to improve the ride comfort and safety.(3)Develop the braking force distribution strategy of regenerative braking system.In order to ensure the motor braking force don't lost during braking,through theoretical analysis of the process of regenerative braking and research on the classic regenerative braking force distribution strategy,develop the economic strategy based on ECE regulation,the strategy includes the distribution of friction braking force and braking force and the front and rear axle braking force distribution etc.At the same time,considering the low adhesion coefficient of road surface such as rain and snow weather,developed a security policy which made maximum utilization of adhesion as the goal,then did the comparison of the simulation results of economic strategy and security strategy,which verified the regenerative braking energy recovery ability of economic strategy.(4)Modeled regenerative braking system and simulated its performance.This paper through AMESim and Matlab/Simulink did a co-simulation,the co-simulation results showed that the shift control strategy could make the output driving torque remained almost unchanged basically in the shifting process in all kinds of driving mode,jerk was less than 10m/s3,so were slipping work,ensured that no sudden withdrawal of the motor braking force occur during the shifting process of braking,and improved the safety and smoothness.Then,the paper selected typical braking conditions with different initial speed and strength and three common conditions,the simulation results showed that the economic strategy had good braking performance,front and rear wheel didn't lock also,ensured the direction stability in braking process,and through comparing with the security policy,verified the regenerative braking energy recovery capacity,the simulation results showed that in JP10-15,NEDC and UDDS cycle,economic strategy increased the efficiency of Regenerative braking energy feedback by 24.79%,15.71%and 25.4%than security strategy.