Research On Power Distribution Optimization Method Of Hybrid Power Supply For Electric Vehicle

Currently,the single battery storage system for electric vehicle has inherent drawbacks,which can not meet the requirements of power output and energy output in the complex and changeable conditions of the vehicle.The hybrid energy storage system integrated by high specific power ultra-capacitor and high specific energy storage battery shows its advantages as a solution.Ultra-capacitors can provide high power output during the start,acceleration and climbing stages of an electric vehicle,reduce the impact of instantaneous high current output demand on the battery,and the battery can continuously provide a stable energy output for the vehicle to drive,making up for the insufficiency of the ultra-capacitor with low specific energy.In order to give full play to the superiority of hybrid storage system and improve energy conversion efficiency,the design of efficient and reasonable power distribution control strategy is one of the key links.Based on,this paper focuses on the structure,energy conversion efficiency,intelligent optimization algorithm,power distribution control strategy of hybrid storage system for EV.The main research work is as follows:(1)This paper reviews the research status of ultra-capacitor/battery hybrid storage system and its power allocation control strategies,analyses the latest research results,compares and analyses the configuration and characteristics of various common hybrid storage systems,and focuses on the optimization algorithm and control strategy of power allocation for hybrid storage systems.(2)The configuration of ultra-capacitor/battery hybrid energy storage system is proposed.Series-parallel switching technology is used to realize the variable voltage output of the energy storage system,thus realizing the multiple working modes of the energy storage system to meet the complex variable operating conditions of vehicles,increasing the power output range of the energy storage system,and facilitating the optimal control of power distribution control.(3)The model of each component of the energy storage system is established,the efficiency model of the energy storage system and the efficiency model of the power converter are given,and the accuracy of the model is verified by simulation and experimental data,which lays a foundation for the power allocation optimization based on the maximization of the energy efficiency of the system.(4)The optimization objective function of hybrid energy storage system is determined,and the flow of power allocation control strategy based on the optimization algorithm is described through systematic study of the optimization algorithm.The power allocation control strategy of hybrid energy storage system based on genetic algorithm and Grey Wolf algorithm is implemented in the hybrid energy storage system.(5)The power allocation control strategy based on rules and the power allocation control strategy based on optimization algorithm are compared and studied.The power allocation control strategy based on genetic algorithm and Grey Wolf algorithm proposed in this paper is verified to be superior and advanced in terms of maximizing energy conversion efficiency,accuracy of power allocation and response capability under complex operating conditions.