Study Of Regenerative Braking Control Strategy For Pure Electric Vehicle

Regenerative braking as a ke y technology for the developmen t of pure electric vehicle,which can not only reduce energy consum ption,but also extend driv ing rang.Moreover,regenerative braking can reduce the abrasion of the friction disk with the participation of motor braking force.This paper is supporte d by the Education Departm ent of Sichuan Province “Study of Braking Energy Recovery for Electric Vehicle” project,on condition that braking safety is ensured,the regenerative br aking control strategy of electric vehicle is studied with the purpose of maximum energy recovery.The main research work in this paper is as follows:(1)The regenerative braking system structure and working theory of electric vehicle is studied,and the influencing factors of regenerative braking are analyzed.On this basis,the reasonable range of braking force distribution coefficient is determ ined according to ECE regulations limit.In order to ensure the requirements of braking safety,motor braking force is constrained by the key factors of motor and battery as well as further modified by introducing the factors of velocity and battery SOC combined with actual situation.(2)The braking directional stability is st udied when m otor braking force and friction force joint brake together.It is concluded that the electric vehicle of front axle driven can not only ensure braking stability,but also bene fit energy recovery.Th e result can provide theoretical basis for driving type selection.(3)Combining with the characteristics of typical regenerative braking control strategy,the control strategy of m aximize energy recovery in this paper is proposed under different road adhesion coefficient based on ECE re gulations.Through the Matlab/Sim ulink,the simulation model of each strategy and contrast analysis model of four kinds of typical strategy are established.The control strategy of ADVI SOR is secondary developed.It provides the simulation experiment platform for control strategy in the paper based on Matlab/S imulink and ADVISOR.(4)This paper has made the simulation experiment of strategy under typical conventional braking condition and city driving cycles.Th e simulation results sh ow that: un der the conventional braking condition,the basic braking performance meet the requirements;under typical city driving cycles,the strategy of this paper has obvious a dvantages.According to braking control strategy comparison of different road adhesion coefficient,affected by speed and braking intense,under the UDDS driving cycles,the energy recovery of strategy under high adhesion coefficient of road is higher th an strategy under low adhesion coefficient of road.The energy recovery of two strategies has no obvious change under ECE driving cycles.The results achieved the goal of strategy in this paper.(5)Based on the m aximize energy recovery strategy under the ECE regulations,this paper researched the further force distribution of front axle by Fuzzy control theory when motor braking force and friction force joint br ake together,and established the simulation model for the optim ization strategy.The simula tion experiment results of Fuzzy strategy show that: under the two typical strategies,the energy recove ry rate has further im proved compared with un-optimized strategy.The regenerative braking strategy research in this pap er establishes the theo ry and practical application foundation for electric vehicle.