Research On Energy Mangement Strategy For Hybrid Energy Storage System Of Electric Vehicle

With the intensification of environmental pollution and energy shortages,electric vehicles have received widespread attention as new energy vehicles.However,traditional electric vehicles only use single energy storage components such as batteries,which have issues such as slow power output,slow acceleration,and energy waste.Compared with traditional single energy storage components,the hybrid energy storage system consisting of a supercapacitor and a battery has advantages such as high energy utilization rate,good power performance,and long service life,and has become one of the hotspots in the research of electric vehicles in recent years.However,the battery and supercapacitor in the hybrid energy storage system have different characteristics and performance,and how to reasonably allocate the power output of the energy storage components,realize energy management and control of different energy storage components,and improve the energy utilization efficiency of the entire system has become a pressing problem that needs to be solved.This paper takes the energy management strategy of hybrid energy storage system for electric vehicles as the research object,and explores the optimization strategy of energy management of hybrid energy storage system.Firstly,by analyzing the structure of commonly used hybrid energy storage systems and the working principle of LLC resonant converter,a fully active circuit topology structure of hybrid energy storage system based on unidirectional/bidirectional full-bridge LLC resonant converter was designed.Secondly,referring to the performance parameter indicators of a certain electric vehicle,the resonant parameters of unidirectional/bidirectional full-bridge LLC resonant converter of hybrid energy storage system were calculated,and the small signal model and controller design method of full-bridge LLC resonant converter were studied.The control parameters were determined,and simulation verification was carried out.Furthermore,a rule-based energy management strategy for hybrid energy storage system was designed.Based on the energy flow mode to be realized,the specific working mode was divided,and the simulation of a single working mode and automatic switching between different modes were completed on MATLAB/Simulink.Finally,a platform of unidirectional/bidirectional full-bridge LLC resonant converter hybrid energy storage system based on TMS320F28335 digital chip control was built,and the control scheme of unidirectional/bidirectional full-bridge LLC resonant converter designed in this paper and the rule-based energy management strategy proposed were experimentally verified.The experimental results show that the parameter design of unidirectional/bidirectional full-bridge LLC resonant converter is reasonable,and can effectively control the system under various working modes,and can effectively control the energy flow of the hybrid energy storage system according to the proposed energy management strategy,further optimizing the performance of the hybrid energy storage system.