Research On Energy Management Strategy And Capacity Optimization Of Tram Hybrid Energy Storage Syste

In recent years,with the continuous progress of the society,the development of the high speed of the urban economy,the modernization of the cities in our country is accelerating,and all kinds of negative problems come to become the problems of sustainable development of modern cities,such as the greenhouse effect caused by the automobile emissions,traffic jams,etc.,more and more areas have begun to develop public transport.Among these public transportation tools,modern tram has become an important means of transportation to realize energy saving and emission reduction and relieve traffic pressure due to its advantages of convenience,safety,environmental protection and economy,moderate volume and cost.Vehicle-mounted hybrid energy storage system trams have many advantages,such as beautiful without net,energy saving and environmental protection,and mature technology.They have become a hot research topic at home and abroad.Aiming at the tram of the hybrid energy storage system with lithium titanate battery/super capacitor,this paper studies the topology of energy storage components,energy management strategy and capacity optimization configuration of the hybrid energy storage system.The specific research work and contents are as follows.(1)Modeling and analysis of hybrid energy storage system,comparing and analyzing the advantages and disadvantages of different hybrid energy storage system topologies according to the characteristics of modern tram driving conditions and the characteristics of each energy storage component,and determining a topology suitable for tram.The equivalent models of supercapacitor and lithium battery were established and suitable energy storage component models were selected to provide theoretical support for the subsequent research.The tram dynamics model is established,and the dynamics analysis is carried out.The tram traction working condition is calculated by combining the domestic tram driving line data,and the tram load power is obtained.(2)Energy management strategy of hybrid energy storage system.Based on the hybrid energy storage system model,an energy management strategy based on energy complementation is proposed,taking the constant power distribution energy management strategy as the basic strategy.This paper analyzes the shortcomings of the hybrid energy storage system under the basic strategy,which cannot give full play to the characteristics of the energy storage components,and will seriously affect the normal running of the trolley.Through the simulation analysis in Matlab/Simulink,the variation curves of voltage,current,SOC and power of each energy storage element are analyzed to verify that the two strategies can meet the normal operation of the trolley.Under the improved strategy,the load power distribution can be more reasonable,more flexible and more practical.(3)Capacity optimization configuration of hybrid energy storage system.The annual running cost function of tram hybrid energy storage system is established,including initial acquisition cost,operating cost and replacement cost.According to the characteristics of each energy storage component and the required power characteristics of the system,considering the constraint range conditions of energy storage component voltage,current,weight,SOC,etc.,the minimum total cost of the hybrid energy storage system was taken as the goal,and the particle swarm optimization algorithm was used to find the optimal goal,that is,the configuration parameters of the hybrid energy storage system with the minimum lifetime cost.The simulation verifies that the trolley can run normally under the optimal configuration of the improved strategy.