The LLC resonant converter is one of the most attractive topologies in many applications, due to its simple structure and zero-voltage-switching capability. However, under wide-input-voltage condition, it has large primary conduction and turn-off switching losses because of small magnetizing inductance. Thus, in this article, the LLC resonant converter using three switches is proposed for high-efficiency under wide universal ac input voltage. These three switches can make two operating modes of LLC resonant converter according to low/high line input conditions. As a result, the proposed converter can be designed with larger magnetizing inductance, resulting in high efficiency. The validity of the proposed converter is verified with a 60-W prototype for high efficiency, almost maintaining the system size, compared with the conventional LLC converter.

中文翻译：

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用于具有通用输入电压的高效适配器的三开关 LLC 谐振转换器

由于其简单的结构和零电压开关能力，LLC 谐振转换器是许多应用中最具吸引力的拓扑结构之一。但是，在宽输入电压条件下，由于励磁电感小，初级导通和关断开关损耗大。因此，在本文中，为了在宽通用交流输入电压下实现高效率，建议使用三个开关的 LLC 谐振转换器。这三个开关可以根据低/高线路输入条件使 LLC 谐振转换器具有两种工作模式。因此，所提出的转换器可以设计为具有更大的磁化电感，从而提高效率。所提出的转换器的有效性已通过 60 W 原型进行验证，以实现高效率，几乎保持系统尺寸，