高频变压器一次侧串联LLC+输出端并联Buck级联直流变换器  

A Cascaded DC Converter with Primary Series Transformer LLC and Output Interleaved Buck

作　　者：石健将[1] 章江铭 龙江涛[1] 刘天骥 

机构地区：[1]浙江大学电气工程学院,杭州310027

出　　处：《电工技术学报》2015年第24期93-102,共10页Transactions of China Electrotechnical Society

基　　金：国家自然科学基金资助项目(51277162)

摘　　要：为满足高压/宽输入、输出低压/大电流以及高功率密度直流模块电源的技术要求,提出一种变压器一次侧串联LLC+输出端交错并联Buck电路的级联高频直流变换器拓扑结构。该级联变换器的前级LLC工作在定频、开环方式,实现电气隔离与降压;后级交错并联Buck电路采用相同占空比、闭环工作方式,实现输出稳压与自然均流。针对该级联变换器的工作模态、LLC的谐振参数设计进行分析;同时,针对高频变压器匝比和Buck电路占空比等参数的不一致性对输出自然均流的影响,也进行了理论分析。最后,仿真和实验均证明了该级联变换器理论分析的可行性与正确性。In this paper, a two-stage DC-DC topology, which consists of primary series transformer LLC and output interleaved Buck, is presented. The proposed topology can be applied in DC power converters of high/wide input voltage, low output-voltage/high output-current and high power density. This cascaded topology makes full use of the high efficiency of the open-loop operating LLC converter with constant switching frequency. Moreover, the electrical isolation and voltage step-down are also realized by the LLC. The output voltage regulation as well as the automatic current sharing is achieved by the second stage interleaved Buck. The operation mode of the cascaded converter and the parameter of the LLC are designed, and the steady-state output current sharing is analyzed even with mismatched parameter. Finally, the theoretical analysis is validated by simulation and experiments.

关 键 词：LLC BUCK 输出自然均流 变压器串/并联 级联变换器 

分 类 号：TM46[电气工程—电器]