一种SEPIC馈电升降压变换器

A SEPIC Fed Buck-Boost Converter

针对光伏电池、燃料电池发电等输出电压范围较宽而输出电流纹波要求较小的特点,提出了一种SEPIC馈电升降压(SFBB)变换器拓扑。该拓扑通过极性反转变换器与SEPIC变换器的耦合电感集成,在继承原有SEPIC变换器与极性反转变换器升降压变换特性的基础上,实现了变换器的开关同步,显著提高了整机工作效率。结合SEPIC输入级额外漏感的续流特性降低了SFBB变换器的电流纹波。此外,通过辅助换向网络,抑制了控制开关的振铃效应;通过门电荷抽取机制实现了控制开关的快速关断,进一步降低了变换器的关断损耗。文中详细分析了SFBB变换器的工作原理,并搭建了一台60 W实验样机,验证了理论分析的正确性。

A SEPIC Fed Buck-Boost（SFBB） converter is proposed for photovoltaic and fuel cell power system, where the converter is desired to interface the power source with low current ripple under wide input voltage range. The SFBB topology realizes synchronous switching and achieves significant efficiency promotion with the inductor coupling of the inverting and SEPIC converters, which still inherits the voltage step-up/-down characteristics. The low current ripple is achieved with the added leakage inductor in the input stage of the SEPIC portion. Besides, the ringing effect of the con- trol switch is restrained with the auxiliary commutation network ; and the inherent gate-charge-extraction mechanism facilitates extremely fast turn-off of the control switch, essentially eliminating the turn-off loss of the SFBB converter. The operational principle of the SFBB converter is analyzed in detail and a 40W prototype is built with experimental results to verify the analysis.