Rsearch On The Energy Storage System Of Super Capacitor

Solar energy is inexhaustible and green energy. The process of solar photovoltaic power generation is simple. It does not consume fuel and it has no noise and pollution, so the photovoltaic technology has been developed rapidly. But due to the influence of season, climate and other factors, the output power of photovoltaic power generation is random and intermittent. Energy storage devices can provide energy storage, which will improve energy efficiency, enhance the system economy and maintain system security and stability. Super capacitor is an energy storage device with high power density, a fast charging and discharging speed, long cycle life, etc. It achieves great development in the field of energy storage. The super capacitor energy storage system is researched and applied to photovoltaic generation system in this paper.Firstly, this paper has a detail description on the working principle and performance characteristics of super capacitor. After summarizing the super capacitor modeling status quo home and abroad, this paper presents a system identification method to model the super capacitors overcome the shortcomings of the existing models,. Then the recursive extended least squares optimization algorithm is used to solve the problem, and then the model’s parameters are obtained. The results of experiments and simulations show that the model presented in the paper can describe the super capacitor’s dynamic characteristics precisely and the modeling method is feasible and Valid. Finally, the model was simulated and verified. Due to the low cell voltage of the super capacitor, the energy storage system needs many super capacitor cells in parallel and series, and the averaging of the voltage among these super capacitors is analyzed.Secondly, this paper designs and optimizes the super capacitor energy storage arrays and tries to find some ways to design the energy storage array, such as how to determinate the size of array, how to optimize the structure of array.The theory and topology of non-isolated bidirectional DC-DC converter based on super capacitor is analyzed in this paper, this paper studies the non-isolated bidirectional conversion technology, especially the outstanding problems during the operation of the typical Buck/Boost topology. This paper also gives the conditions of eliminating oscillations and achieving soft switching based on the above analyses. The calculation method of the main parameters of the converter is introduced in this field. The results were simulated and verified. Finally, this paper also discusses the stability and dynamic characteristics of the open loop small signal model in the main power circuit. To achieve stability and fast response, a new control strategy and approach for designing the controller is proposed. The current controller is based on Boost circuit, while the voltage controller is based on the bus voltage. Energy storage system of super capacitor model is built based on MATLAB/SIMULINK. and the correctness and validity of the system and its control strategy are confirmed.