基于GaN全桥LLC谐振变换器交错并联系统的损耗分析

Loss analysis based on staggered parallel system of GaN full bridge LLC resonant converter

为提高全桥LLC谐振变换器交错并联(FBLLC-SP)系统的效率,且使其理论损耗与实际运行损耗更贴近,对比Cascode型GaN HEMT向系统引入单体增强型GaN HEMT,并将其寄生参数引入到损耗模型中,建立了一种适用于单移相(SPS)开环控制和三移相(TPS)双闭环控制的FBLLC-SP系统精准损耗模型;给出最佳死区时间计算方法,并分析了FBLLC-SP系统在单移相(SPS)开环控制下的理论损耗,提出了不同模态GaN HEMT的暂态损耗和各种通态损耗的精准计算方法;搭建了FBLLC-SP系统损耗模型仿真系统。实验结果表明:本文损耗模型的损耗值比系统实际运行损耗最多高约0.6%,说明本文建立的精细化损耗模型可用于分析系统的实际运行损耗。

In order to improve the efficiency of the staggered parallel system of the full bridge LLC resonant converter(FBLLC-SP),and make its theory loss closer to the actual operation loss,contrasted with the Cascode type GaN HEMT,the monomer enhanced GaN HEMT is introduced into the system,and its parasitic parameters is taken into consideration in the loss model.FBLLC-SP system precision loss model for the single phase shift(SPS)open loop control and three phase shift(TPS)double closed loop control is set up.The optimal dead zone time calculation method is given.The theoretical losses of FBLLC-SP system under SPS open-loop control are analyzed.The accurate calculation methods of transient loss and on-state loss of GaN HEMTs with different modes are proposed.The loss model simulation system of FBLLC-SP system is built.The experimental results show that the loss obtained from the loss model in this paper is about 0.6%higher than the actual operating loss of the system.It illustrates that the refined loss model established in this paper can be used to analyze the actual operating loss of the system.