Research On Digital Simulation Model And Its Implementation Of The Super Capacitor Energy Storage System

Since the 21 st century, under the pressures of energy and environment, the distributed power generation technology is developing rapidly. The randomness of new energy sources such as wind power and solar energy will lead to the volatility and intermittent of the distributed power’s output power, so with the network scale of distributed power increasing, it will impact the reliability and power quality of the grid. Energy storage technology can pro vide the grid with instantaneous power support and short time power support, and the usage of distributed power generation with the combination of energy storage technology will be the key means to reduce the grid impact. As a new type of power energy stor age device, supercapacitor has the advantage of large power density and fast response, and with the increase of its capacity, it will make distributed power connecting to the grid smoothly possible. In this paper, based on the supercapacitor and the requirement of power system simulation calculation, accurate supercapacitor’s monomer simulation model is established, and systematically stud y is conducted in the supercapacitor energy storage system’s applications and modeling.First of all, the classification, the running mechanism and the charging and discharging characteristics of supercapacitor is elaborated in detail. Based on the modeling status quo, a grid second order model of electric double layer super capacitor has been put forward, which is suitable for grid simulation, and the classic method of determining its model parameters has also been given by using the classical parameters, the parameter sensitivity analysis has been done as well. On this basis, constant current and constant power charge-discharge experiment is carried out respectively on 16.5F and 33 F supercapacitor, and the data obtained in the experiments was used to complete the parameter identification of the two order model with the comprehensive improvement of genetic algorithm, the iden tification error is below 5%, and qualitatively analysis of the relationship between model parameters and the capacitance was made.The topology and operation principle of the supercapacitor energy storage system based on 30 k W supercapacitor energy storage system was studied in the dynamic simulation laboratory, achieving the basic test of supercapacitor involving in network micro UPS and unit FM by connecting to the laboratory power grid. On this basis, this paper introduces the control strategy of bi-directional DC/DC converter and bi-directional DC/AC converter and build s a detailed simulation model for supercapacitor energy storage system based on Matlab/Simulink simulation platform, its correctness and validity was verified by simulation experiments.Finally, in order to study the dynamic characteristics of supercapacitor energy storage system, the detailed simulation model was connected to the four-node grid simulation system for transient experiments, supercapacitor energy storage system integrated equivalent model is proposed according to its dynamic characteristics, and parameters identification was conducted with genetic algorithm. By setting up different malfunctions in the simulation system and applying co-simulation in power system simulation software PSASP, the proposed model has been proven to have good description ability, parameter stability and applicability.