| In recent years, with the rapid development of power electronics, UPS also tends to high-frequency technology, miniaturization and digitization, but with the traditional hard-switching mode, the switching loss and electromagnetic interference and other issues become increasingly prominent. Therefore, the research and application of soft-switching circuit becomes very significant. This paper, aimed a Buck-Boost discharge circuit of traditional UPS topology, using passive lossless soft-switching technology, researches on a Buck-Boost passive lossless soft-switching topology. The efficiency increases up to 95%, and 8% more than hard switching mode. It has achieved obvious results.Firstly, this paper analyzes the design principles of lossless passive soft-switching, identified the position of zero-current inductors, zero-voltage capacitor of Buck-Boost lossless passive soft-switching circuit, and transient energy renewable reset sub-loop. In the end, it introduced the topology.Secondly, the paper has an analysis on the work mode and device stress, and discusses the realization of soft-switching. In addition, it researches the simulation using Pspice. The results show that this topology can achieve zero-current when turning on and zero-voltage when turning off.Thirdly, it builds a non-ideal mathematical model in the continuous mode of Buck-Boost converter, and analyzes the working principle and concrete realization of average current controlling mode. Furthermore, it satisfies the requirements that make the output of the closed-loop circuit stable.Finally, the paper shows the design parameters of the hardware circuit, including the main power circuit, control circuit, driver circuit. In addition, it builds a converter to verify the conclusions of theoretical analysis and simulation analysis. The experimental results show that passive lossless soft-switching links can achieve zero-current when turning on and zero-voltage when turning off. |
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