High voltage step-down converters are very popular in distributed power systems, voltage regular modules, automatic vehicles, etc. To avoid extreme duty cycles, a series capacitor-based buck converter with a coupled inductor is proposed in this paper. In this converter, the voltage stresses of the power switches are clamped to half of the input voltage. Thus, low voltage rating MOSFETs with a low Rds,on could be utilized to improve the performance of the proposed converter. Moreover, synchronous MOSFETs are also used to reduce the conduction losses of the switches. Zero voltage switching (ZVS) for the main power switches is achieved using the coupled-inductor technique. In addition, through adding a bypass flowing path, a negative current is established to guarantee the ZVS condition of the power switches. The operating principle of the proposed converter is described in this paper, and the DC voltage gain ratio, automatic current sharing, soft switching condition and design guideline of the critical parameters are also given. Finally, experimental results obtained from a 60 V/200 W prototype are presented to verify the analysis of the proposed converter.

中文翻译：

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采用耦合电感技术的软开关高降压串联电容器转换器

高压降压转换器在分布式电源系统、电压规则模块、自动车辆等中非常流行。为了避免极端占空比，本文提出了一种带有耦合电感器的串联电容器降压转换器。在该转换器中，电源开关的电压应力被钳位到输入电压的一半。因此，可以利用具有低 Rds,on 的低额定电压 MOSFET 来提高所提出的转换器的性能。此外，同步 MOSFET 还用于降低开关的传导损耗。主电源开关的零电压开关 (ZVS) 是使用耦合电感技术实现的。此外，通过增加旁路流路，建立负电流以保证功率开关的ZVS条件。本文描述了所提出的转换器的工作原理，并给出了关键参数的直流电压增益比、自动均流、软开关条件和设计指南。最后，展示了从 60 V/200 W 原型获得的实验结果，以验证所提出的转换器的分析。