In this paper, we propose a lossless snubber cell for a soft-switched bidirectional buck–boost converter (BBC). The proposed snubber cell provides all switches with soft-switching conditions in both the bidirectional power flows of the BBC. In addition, the cell also achieves a relatively low circulating current for the snubber operation over a wide load range. In particular, the reverse recovery problem of the synchronous rectifier can be eliminated with the aid of the snubber inductor. Accordingly, the snubber cell enables high-frequency switching of approximately 60 kHz for all power switches and achieves high efficiency and high power density. Moreover, the proposed snubber cell does not have any auxiliary switch; therefore, complex auxiliary circuits or driving algorithms for the auxiliary switch are not required. Therefore, the proposed snubber cell has a simple structure with high reliability. To confirm the validity of the proposed lossless snubber cell, we provide detailed analyses, design guidelines, and experimental results using a 3-kW laboratory prototype.

中文翻译：

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用于软开关双向降压-升压转换器的无损缓冲单元

在本文中，我们提出了一种用于软开关双向降压-升压转换器 (BBC) 的无损缓冲单元。提议的缓冲单元在 BBC 的双向功率流中为所有开关提供软开关条件。此外，该电池还在较宽的负载范围内为缓冲器操作实现了相对较低的循环电流。尤其是可以借助缓冲电感消除同步整流器的反向恢复问题。因此，缓冲单元能够为所有功率开关实现大约 60 kHz 的高频开关，并实现高效率和高功率密度。此外，建议的缓冲电池没有任何辅助开关；因此，不需要复杂的辅助电路或辅助开关的驱动算法。所以，所提出的缓冲电池结构简单，可靠性高。为了确认所提议的无损缓冲电池的有效性，我们使用 3 kW 实验室原型提供了详细的分析、设计指南和实验结果。