Research On Optimization Of Hybrid Energy Storage System Energy Distribution Strategy For Electric Vehicle Considering Driving Style

In recent years,mankind is facing more and more severe pressure on resources and environment,which makes the development of electric vehicles more and more valued by people and promotes the rapid development of electric vehicle technology.Battery is one of the core components of electric vehicles.When electric vehicles drive in cities,the high-power charge and discharge demand generated by frequent acceleration and braking will accelerate the irreversible capacity decline of lithium-ion batteries.Therefore,the super capacitor with high power density is combined with it to form a hybrid energy storage system to reduce the capacity attenuation of lithium-ion batteries and prolong the service life of lithium-ion batteries.However,the use of super-capacitor also brings about the disadvantages of high cost,large weight and low system efficiency in the hybrid energy storage system.In view of this contradiction of hybrid energy storage system,this paper proposes to take the real electric vehicle driving data in the city as the research data,introduce the driver style to optimize the energy distribution strategy of hybrid energy storage system,and improve the intelligence of energy management system.The main research results of this paper are as follows:(1)Through the electric vehicle urban road driving experiment,26 groups of driving data of different drivers are collected.According to the 8 characteristic parameters related to energy consumption,these driving data are divided into three different driving styles by principal component analysis and cluster analysis,and the influence of each driving style on energy distribution is analyzed.(2)The model of lithium-ion battery and supercapacitor is established,and the topology of the hybrid energy storage system is improved to reduce the energy loss of the hybrid energy storage system and protect the supercapacitor from overcharge.(3)According to the improved topology,the energy distribution strategy of multi-mode control is redesigned,and gray wolf optimization is used to optimize the output threshold of lithium-ion battery and the upper charging limit of super capacitor.The optimization cost function is established,and different optimization weights are assigned to the two optimization objectives of lithium-ion battery capacity attenuation and energy loss based on the analysis of different driving styles.(4)Based on the above model,improved topology and control strategy,the advisor software is redeveloped,and the simulation model of hybrid energy storage system and its control strategy is established.The multi-mode control parameters optimized by gray wolf optimization algorithm are substituted into the simulation model,and the simulation results are compared with the results of multi-mode control and its topology before optimization.The results show that compared with the non optimized multi-mode allocation strategy and the traditional semi-active topology,the lithium-ion battery capacity attenuation and system energy loss under the aggressive driving style are reduced by 37.89%and 12.45%;Under the cautious driving style,they decreased by 21.95%and 56.11%respectively.Through in-depth analysis of simulation results,future research should focus on joint optimization with topology and parameter matching,driving style adaptive weight and super capacitor intelligent power replenishment strategy.