| In recent years,due to the extensive use of fossil energy,it has brought a series of serious problems to the ecological environment.Actively developing and utilizing solar energy and promoting clean and low-carbon development of energy has become an important measure to alleviate current environmental pollution and climate change.However,the power generation of solar energy is determined by light intensity,which has great uncertainty,how to store and reuse solar energy more effectively is the direction of new energy technology research.Therefore,DC/DC converters capable of controlling energy bidirectional flow are indispensable in the application of new energy technologies.This paper is directed to a bidirectional DC/DC converter for charging and discharging battery in the household energy storage system.By combining the resonant soft switch and the bidirectional half bridge,the auxiliary magnetizing inductance is added in the traditional inductor-inductor-capacitor(LLC)resonant network.The bidirectional LLC soft switching characteristic of the converter is realized,and the power density of the converter is improved.The specific research contents are as follows:(1)Explain the research progress and application status in the field of new energy.The current developments of photovoltaic power generation and new energy electric vehicles are analyzed.It also briefly describes the household photovoltaic energy storage system combined with photovoltaic and energy storage technology and its working mode.At the same time,the related topology and control methods of bidirectional DC/DC converters are summarized,and the advantages,disadvantages and applications of different bidirectional DC/DC topologies are analyzed.(2)A novel bidirectional LLC resonant DC/DC topology is proposed.In order to meet the power density and cost requirements of bidirectional DC/DC converters in residential PV energy storage systems,a novel bidirectional LLC resonant DC/DC topology is proposed,and various working modes of the topology are analyzed in detail.At the same time,the open-loop simulation experiment of the converter is carried out through the PSIM simulation platform,which verifies the feasibility of the proposed topology.(3)The detailed calculation of the parameters of the bidirectional LLC resonant DC/DC converter is given.By analyzing the forward and reverse directions of the converter,the gain characteristic curve of the converter is given and its working characteristics are analyzed.On this basis,according to the requirements of the converter application,the design parameters and key device selection of the converter-related resonant components are given in detail,which provides specific design guidance for prototype production.(4)An experimental prototype was designed and fabricated.Under the guidance of design parameters,the experimental prototype based on bidirectional LLC resonant DC/DC converter was designed and fabricated for practical application,and the hardware and software design of the prototype was explained in detail.Furthermore,the forward and reverse experiments in multi-operation mode are carried out through the prototype experimental platform.At the same time,the prototype efficiency in forward and reverse directions is given,and the correctness and effectiveness of the proposed topology are further verified. |
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