Research On Capacity Optimization Of Energy Storage System Of Super Capacitor-battery

In order to achieve energy recycling in the pulsating high power load system,and achieve the goal of "Reduce cost,Increase efficiency,Save electricity,Reduce pollution”;In order to smooth the unstable power of the photovoltaic system,stabilize the disturbance brought by natural environment factors and load fluctuation,improve the power quality and reliability of grid connected,and perfect the stability characteristics of photovoltaic power generation system,the introduction of energy storage technology is inevitable trend,and the research on energy storage technology is of great significance.This paper presented a capacity optimization method of hybrid energy storage system constituted by super capacitor and battery.Firstly,empirical mode decomposition(EMD)resolves imbalanced power,to obtain high frequency power components and low-frequency power.Super capacitor is responsible for the high frequency power,battery is for low-frequency power component.This method has showed the advantages of super capacitor with high cycle life and of battery with higher power density and energy density.The converter is considered as independent individuals,and its operation mode and cost are contained in the whole life cycle cost of objective function of hybrid energy storage system,which makes the calculation result more accurate.According to the two constraints of the loss of power supply probability and the loss of produced power probability,use the genetic algorithm to solve the objective function.This article applied the capacity optimization configuration method of hybrid energy storage system to three different kinds of power supply system,high power pulse load system,photovoltaic independent power supply system,unified purchase and marketing mode of photovoltaic grid power generation system.Firstly,three kinds of system structure and working principle were introduced,so the hybrid energy storage system is needed in three systems,then the paper built up the capacity optimization model of super capacitor and battery hybrid energy storage system in different systems,and a calculation is made for instance.Results shows the proposed hybrid energy storage system can avoid the waste of electricity and reduce the pollution of the environment in high power pulse load system;the proposed hybrid energy storage can effectively ease the power fluctuation,stable dc bus voltage,and improve of the photovoltaic power quality in independent photovoltaic system;the proposed hybrid energy storage system can realize the reasonable use of energy resources and improve the economic benefit of the whole system in unified purchase and marketing mode of grid-connection photovoltaic system.In this paper,the proposed method can give full play to the advantages of super capacitor and battery and realize the running of system economics.Because the cost took inverter into account,this configuration method made capacity calculation more accurate.