Research On Supercapacitor Energy Storage Device Simulation Modeling And Its Applications

Renewable distributed generation such as wind power generation, photovoltaicpower generation, is widely connected to t he grid in recent years, but due to theinfluence of season, climate and other factors, the output power is random andintermittent. With distributed power capacity in the grid continually increasing, it willhave a large impact on grid security, stability, power quality and even lead tolarge-scale serious accident. Energy storage technologies can provide energy storage,balance and spare for distributed generation systems, which will improve energyefficiency, enhance the system economy and maintain system security and stability.Supercapacitor as a new type of energy storage devices with fast dynamic response,high efficiency, high power density, long cycle life, etc., is a very promising energystorage device. Therefore, this paper systematically studies the supercapacitorworking principle, equivalent modeling, the voltage balancing and the energy storagesystem simulation modeling.Take an electric double layer supercapacitor as an example, this paper have adetail description on the working principle and performance characteristics ofsupercapacitor. After summarying the supercapacitor modeling status quo at home andabroad, this paper presents a new type supercapacitor model—advanced2RC model toovercome the shortcomings of the existing model s. A set of identification method isalso given to quickly determine model parameters by constant current chargingexperiment. Owing to its simple structure, good description capability and readilyidentifiable parameters, this model has high engineering practical value. Usingperturbation analysis method, this paper conducts a sensitivity analysis of keyparameters of the model to analyze the impact of the specific performancecharacteristics of the supercapacitor dominant factor s, in order to provide a basis forfurther optimization adjust of the model parameters.For supercapacitor voltage balancing problem, based on the analysis of the factorsthat affect the supercapacitor voltage, this paper has a detailed analysis of the workingprinciple, advantages and disadvantages of the the existing supercapacitor voltageequalizer control strategy. Voltage equalizing simulation has achieved good resultswith advanced2RC model as a monomer model and the single flying capacitormethod as the voltage sharing strategy,which is a good foundation for supercapacitor group modeling.This paper has conducted a detailed analysis of the structural composition andoperation principle of supercapacitor energy storage system. Based on themathematical models of bidirectional DC/DC converter and the grid-side converter,their control strategy are discussed minutely. Supercapacitor energy storage systemmodel is built based on Matlab/Simulink, and the correctness and validity of thesystem and its control strategy are confirmed. Suportted by wind power data fromnational wind/photovoltaic/energy storage and transmission demonstration project,thissupercapacitor energy storage system is used for the smooth wind turbine outputfluctuations,achieving good smoothing effect.