Reversible Sepic-Zeta Converter Reserch

The bidirectional AC/DC converter can realize the energy transmission between the DC and AC side, because of which it plays an important role in the solar photovoltaic power generation system. However, the traditional full bridge bidirectional AC/DC converter only can realize the boost convert. What’s worse, the solar photovoltaic power generation system’s output voltage is fluctuating badly because of environment influence.In order to solve the above-mentioned problems, a single-stage bidirectional AC/DC converter is proposed in this paper, which not only can realize the energy transmission between the DC and AC side but also can implement the buck/boost convert.This paper presents a novel reversible Sepic-Zeta converter by reading large numbers of domestic and foreign related literatures, analyzing the characteristic of traditional full bridge bidirectional AC/DC converter, and combining the thought of compose the inverter through the combination of six basic DC/DC circuit. Compared with the traditional full bridge bidirectional AC/DC converter, the bidirectional AC/DC converter proposed in this paper not only can realize the boost convert, but also can realize the buck convert, which overcomes the shortcomings of the full bridge bidirectional AC/DC converter. According to the design feature of the reversible Sepic-Zeta converter, semi-cycle control and full cycle control are applied to control the converter. The detail of working principle and modulation has been analyzed for the reversible Sepic-Zeta converter of two control methods. On these basis, obtaining the small signal model of the reversible Sepic-Zeta converter with the state-space averaging method. The close-loop control method and simulation analysis have been accomplished when reversible Sepic-Zeta converter is working in rectifier mode and inverter mode respectively. Finally the reversible Sepic-Zeta converter has been integrated into a set of control system with improved performance.On the basis of theoretical analysis and simulation results, the main circuit and control circuit of reversible Sepic-Zeta converter has been designed. At the same time, this paper has implemented the software design and built a 200 W prototype. The experimentalresults verified the feasibility and correctness of the theoretical analysis of the control scheme.