基于并联变压器切换的LLC谐振变换器宽范围效率优化控制策略  

Wide Range Efficiency Optimization Control Strategy for LLC Resonant Converter Based on Parallel Transformer Switching

作　　者：刘晓东[1] 董保成 吴慧辉 方炜[1] 刘宿城[1] Liu Xiaodong;Dong Baocheng;Wu Huihui;Fang Wei;Liu Sucheng(Key Lab of Power Electronics&Motion Control Anhui University of Technology,Maanshan 243000,China)

机构地区：[1]安徽工业大学电力电子与运动控制重点实验室,马鞍山243000

出　　处：《电工技术学报》2020年第14期3018-3029,共12页Transactions of China Electrotechnical Society

基　　金：国家自然科学基金(51407003);安徽省自然科学基金(1708085ME106);安徽高校自然科学研究重点(KJ2017A067)资助项目。

摘　　要：提出一种基于并联变压器切换控制的LLC(ST-LLC)多谐振腔软开关直流变换器。基于变电感比值k的设计思想,采用多变压器间接并联方法以及切换控制策略构建新的变拓扑结构LLC,在保持软开关特性的同时,实现对变换器效率的有效提升以及对变压器热点的分散设计。对拓扑电压增益特性以及主要工作模态进行详细分析,为变换器工作模式设置提供了理论依据。给出变压器切换控制逻辑,并在此基础上,提出一种最优负荷分区控制策略,拓宽了LLC变换器的高效工作范围。此外,详细推导变压器切换控制点最大功率解析式,给出电路主要元件参数设计流程,并设计制作了一台约1kW的电源样机,通过仿真和实验共同验证了所提方案的可行性,样机实现了在82%的负载范围内保持90%以上的工作效率。A parallel switching transformer-based LLC(ST-LLC)multi-resonant converter was proposed in this paper.The transformer indirect parallel method and switching control strategy were used to construct a novel variable topology LLC based on the idea of variable inductance ratio k.The efficiency of the converter was effectively improved and the decentralized design of the transformer hot-spot was achieved,while maintaining soft switching characteristics.Detailed analysis for characteristics of voltage gain and the main operating modes was given.Besides,an optimal load partition control strategy was proposed based on the logic of transformer switching control,and wide range of high efficiency was achieved.Furthermore,the analytical formula of the maximum power of the transformer switching point was derived,and the design process of the main component parameters of the circuit was also given.A 1kW prototype was designed and manufactured,and the feasibility of the proposed scheme was verified by simulation and experiment.The working efficiency of the prototype could maintain more than 90%in the 82%load range.

关 键 词：LLC变换器 并联变压器切换 效率优化 最优负荷分区控制 

分 类 号：TM46[电气工程—电器]