Research Of Bidirectional Full Bridge DC/DC Converter Of LLC Resonant

Because the traditional fossil energy has caused gre at pollution to the environment, the development of new energy is becoming more and more important. As the key process of energy converison, Bidirectional DC /DC Converters(BDCs) are widely used in new energy sources, such as Hybrid electric vehicles(HEVs), uninterrupted power supply(UPS) and photovoltaic power generation system, etc. It is very important to improve the efficiency of the BDCs for the development of new energy sources.In the high-power BDCs, the Bidirectional Full Bridge DC/DC Converters have the characteristics of low voltage stress, high power conversion efficiency and high power transmission. On the basis of the Bidirectional Full Bridge DC /DC Converters, and combined with the advantages of the LLC resonant circuit to achieve full load zero voltage switching, wide range input voltage and high power conversion efficiency, this paper gives a deep research on the LLC Resonant Bidirectional Full Bridge DC/DC Converter.Firstly, in this paper, the working principle of LLC Resonant Bidirectional Full Bridge DC/DC Converter is analyzed, and the open loop simulation and verification is carried out. Based on the topological structure of converter, this converter is analyzed the fundamental component modeling method a nd voltage gain characteristics, and propose a new design principle o f resonant parameters. Combined with the actual circuit, the influence of the error of the resonant parameters on the converter is analyzed. Finally, the loss of the converter is analyzed.Secondly, the control method of the converter bidirectional flow is studied. This method enables the bidirectional DC/DC converter to realize the automatic switching of the positive and negative jobs, and the closed- loop simulation is carried out to verify the good dynamic performance of the converter.Finally, the hardware and software of the bidirectional converter are analyzed and designed, and the software flow chart of the system control is given. On this basis, the experimental platform is built, and the forward and reverse experiments are carried out. The experimental results are consistent with the theoretical analysis, which proves the correctness of the theoretical analysis.