中文摘要：

针对现有第4类LLC谐振型DC—DC变流器拓扑种类繁多，研究芜杂的现状，该文在总结第4类LLC谐振型变流器基本特性及分析方法的基础上，从模块电路功能辨识的角度出发，将该类变流器拓扑重新统一构建在一个由若干基本功能电路模块组成的宏模型内，并探求归纳其所有基于此宏模型的功能电路模块准同构拓扑形式。这些拓扑形式保留了第4类LLC谐振型DC—DC变流器的特征和优点，可根据输入输出及磁隔离要求而分类，并具有各自适用的应用场合，是电力电子系统集成优选拓扑类。进而，这些拓扑可柔性改造成诸多变形形式，从而适用于一些特殊应用，例如高压输入及高效率多路输出场合。最后，用一个适用于不间断电源（uninterruptible power supply，UPS）系统后备模式直直转换的样机验证第4类LLC谐振型DC—DC变流器准同构拓扑及变形形式的多样性和在工业应用中的有效性。

英文摘要：

All kinds of quasi-isomorphic topologies dedicating to the type-4 LLC series resonant converter have been explored and researched on basis of module function identification. These topologies, which varying from the input and output structures with different isolation requirements and could be represented in a canonical macro model consisting of basic circuit module with the same functions, have their own potential useful properties while maintaining the same characteristics and possessing all merits of the original type-4 LLC converter. Consequently, each of the presented topologies could be a candidate for the specific application in which it is suitable for and all of them consist of a preferred topology category for power electronics integration. Furthermore, by being appropriately modified, the presented topologies can flexibly change to some applicable variations that are favorable for rigorous applications such as ultra-high input and high efficiency cost-effective multi-output occasions. Finally, from theory to practical, an example verified the variety and high applicability of type-4 LLC resonant converter and its variations for practical applications in industry.