一种高效率LLC⁃Buck级联谐振变换器  

High-efficiency LLC-Buck cascaded resonant converter

作　　者：李长云[1] 杨艳 徐曦[1] LI Changyun;YANG Yan;XU Xi(Hunan Key Lab of Smart Information Reception and Processing Technology,Hunan University of Technology,Zhuzhou 412000,China)

机构地区：[1]湖南工业大学智能信息感知及处理技术湖南省重点实验室,湖南株洲412000

出　　处：《现代电子技术》2021年第12期31-34,共4页Modern Electronics Technique

基　　金：国家重点研发计划子课题(2018YFB1700204);2018年湖南省教育厅科学研究项目(18K077);湖南省重点领域研发计划课题(2019GK2133)。

摘　　要：为适应目前变流产品高频化、高效率化的发展趋势,该文提出一种高效率的LLC⁃Buck级联谐振变换器。该文分析了全桥LLC谐振变换器的工作原理和特点,推导其直流增益公式,设计主电路的谐振网络参数。前端电路采用LLC谐振变换器,后端电路采用基于lm20343的buck变换器。该电路保留了LLC谐振电路软开关的特性,降低了后端输入电压的电磁干扰。LLC⁃Buck级联变换器的两个输出中的一个是LLC谐振变换器的输出,另一个是LLC谐振变换器,变换器是输入经Buck变换器降压后的输出。最后,搭建1台250~420 V输入,24 V/10 A,12 V/3 A输出的实验样机,实验结果验证了理论分析的正确性。An effective LLC-Buck cascade resonant converter is proposed to suit for the development trend of converter products with high frequency and high efficiency.The working principle and characteristics of full-bridge LLC resonant converter are analyzed.Its DC gain formula is deduced.The resonant network parameters of the main circuit are designed,which are beneficial to improve the conversion efficiency,and can effectively solve the problem of the inductor current disturbance during the startup of the switching power supply.The spike voltage generated during the startup process is removed,and the output voltage is smoothly increased.The topology,working principle and working characteristics of the LLC-Buck cascade converter are analyzed in detail,and the design process is elaborated.An experimental prototype with 250~420 V input,24 V/10 A and12 V/3 A output was built.The experimental results verified the correctness of theoretical analysis.

关 键 词：LLC谐振变换器 BUCK变换器 工作模态 电路设计 时域分析 电磁兼容 实验分析 

分 类 号：TN624-34[电子电信—电路与系统] TM46[电气工程—电器]