Research On Key Technologies Of Power Distribution For Electric Vehicle Hybrid Energy Storage

In recent years,the global energy crisis and pollution problems have become increasingly prominent.Thus it is predicted that EV will replace the traditional fuel vehicles in the future within fuel vehicle ban spreading in various countries.In EV a high energy density energy storage system is vital to provide high-energy and high-power.However,this demand cannot be met solely by a single battery or supercapacitor respectively.Therefore,it is necessary to combine high specific power supercapacitors and high specific energy batteries.Reasonable configuration and power allocation strategy could fully utilize advantage characteristics of above two things.Therefore,under this design previous shortcomings of single energy storage system could be made up,which optimize the daily performance of EV drastically.This paper focus on above research work to provide serval innovative points as follows,(1)Aiming to solve several questions in current hybrid energy storage system,such as passive energy waste,semi-active and active control difficulties,etc.,this paper propose a new active hybrid energy storage system topology within considering device cost and energy recovery efficiency factors.The one-way DC/DC converter is used to replace the traditional two-way DC/DC converter in this design.And this configuration could realize the diversity and high efficiency of power distribution of hybrid energy storage system,which improve the driving efficiency of supercapacitor to motor and the flexibility of power distribution.(2)On the basis of research work(1),the State of Charge(SOC)of storage battery is estimated emphatically.The data of internal resistance,temperature,voltage,current and SOC are collected by experiments in this paper.After comparison,it is found that the internal resistance determines the health status of the battery and affects the rated capacity of the battery in SOC estimation.However,the influence of internal resistance on SOC is seldom considered in the existing literature.A fuzzy control four-inputs-one-output simulation model is proposed,which takes the voltage,current,temperature and internal resistance of power battery as input,SOC as output.Compared with existing research methods,he internal resistance and temperature are added in this paper as the influencing factors of battery SOC estimation.The simulation results show that four inputs have better accuracy.(3)On the basis of the research work(1)and(2),fuzzy neural network model is established in this paper,which has battery SOC,supercapacitor SOC and required power as input and power allocation factor as output.And the simulation experiment of a new configuration of hybrid energy storage system is carried out by using ADVISOR after secondary development,compared with the traditional semi-active method that uses fuzzy control as power distribution control strategy,which further verifies the superiority of this method in battery performance and energy utilization of supercapacitor.