一种适应于直流微电网的全桥LLC变换器  

A full⁃bridge LLC converter suitable for DC microgrid

作　　者：国梦珠 陈思 郑贞钰 郭永玉 GUO Mengzhu;CHEN Si;ZHENG Zhenyu;GUO Yongyu(College of Elecrical and New Energy,China Three Gorges University,Yichang 443000,China)

机构地区：[1]三峡大学电气与新能源学院,湖北宜昌443000

出　　处：《现代电子技术》2025年第2期29-34,共6页Modern Electronics Technique

摘　　要：针对传统的光伏并网隔离型变换器的变压器体积大、损耗高和半导体器件电压应力高等问题,提出一种基于LLC谐振变换器的高增益DC-DC变换器。该变换器满足了输入输出之间电气隔离的要求,将全桥LLC谐振变换器与开关电容相结合,有效地提高了变换器的增益,减少了变压器的体积和损耗,降低了半导体器件的电压应力,实现了开关管的零电压开通和二极管的零电流关断,有效地降低了开关损耗。首先对所提变换器的工作原理进行详细分析;其次用基波分析法分析其基本特性,并进行半导体器件电压、电流应力计算及电路的参数设计;最后搭建一台了800 W的实验样机,经过实验验证,该变换器实现了开关管的ZVS开通,二极管的ZCS关断;减小了变压器的体积和铜耗;转换效率最高可达94.9%。二次侧二极管的电压应力为输出电压的12,是全桥整流的0.5倍、半桥整流的0.25倍,且平均电流相同,有利于器件的选型,更适用于直流微电网的应用,证明了理论分析的准确性。In allusion to the problems of large transformer volume,high loss and high voltage stress of semiconductor devices in traditional grid-connected isolated photovoltaic converter,a high-gain DC-DC converter based on LLC resonant converter is proposed.The converter can meet the requirements of electrical isolation between input and output.By combining the full-bridge LLC resonant converter with switching capacitors,the gain of the converter is increased effectively,the volume and loss of the transformer are reduced,the voltage stress of semiconductor device is lowered,and zero voltage switching of the switching tube and zero current switching of the diode are achieved,effectively reducing switching losses.The working principle of the proposed converter is analyzed in detail,its basic characteristics are analyzed by means of fundamental wave analysis method,and the voltage and current stress of semiconductor devices are calculated and the circuit parameters are designed.An 800 W experimental prototype is built to prove the accuracy of the theoretical analysis.The experimental verification that the converter can realize ZVS turn-on of the switching tube,ZCS turn-off of the diode,and reduce the volume and copper consumption of the transformer.The highest conversion efficiency can reach 94.9%.The voltage stress of the secondary diode is 12 of the output voltage,which is 0.5 times that of full bridge rectification,and 0.25 times that of half bridge rectification.The average current is the same,which is beneficial for the device selection and more suitable for the applications in DC microgrids,proving the accuracy of theoretical analysis.

关 键 词：直流微电网 LLC谐振变换器 DC-DC变换器 高增益 电压应力 开关电容 基波分析法 

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