摘要
与传统变频控制LLC谐振变换器相比,定频移相控制LLC谐振变换器具有磁性元件设计简单的优点。但在输入电压和负载宽范围变化时,定频控制LLC谐振变换器存在环流损耗较大引起效率降低的问题。针对以上问题,本文提出了混合模式定频控制的改进型LLC谐振变换器,能够显著地拓宽变换器的电压增益范围,使LLC变换器能够适应更宽范围的电压输入,同时,提高了变换器的效率,且控制结构简单,易于实现。变换器所有开关管均能实现零电压导通(ZVS),副边整流二极管能实现零电流关断(ZCS),且电路环流损耗较小。结合状态平面轨迹模型,对混合模式定频控制的改进型LLC谐振变换器进行了理论分析,推导了电压增益的表达式以及开关管软开关的实现条件;并通过一台120~400 V输入、300 W/48 V输出的实验样机验证了理论分析的正确性。
Compared with the traditional LLC resonant converter with frequency conversion control,the LLC resonant converter with fixed frequency and phase shift control has the advantages of simple design of magnetic components.However,when the variation ranges of input voltage and load are wide,the efficiency of fixed frequency-controlled LLC resonant converter becomes poor due to large circulating current.To solve the above problems,an improved LLC resonant converter with hybrid-mode fixed frequency control was proposed,which can significantly broaden the voltage gain range of the converter and make the LLC converter adapt to a wider range of voltage input.At the same time,the efficiency of the converter was improved,and it is simple to implement.In the control structure switches of the improved converter,zero voltage switch(ZVS)was achieved,and in the secondary rectifiers diode,zero current switch(ZCS)was achieved,and the circulating current loss is small under all input voltage and output current conditions.The hybrid mode fixed frequency controlled in improved LLC resonant converter was analyzed theoretically in detail by the state plane trajectory model,and the expression of voltage gain and the realization condition of soft switch were derived.Correctness of the theoretical analysis is verified by an experimental prototype with 120-400V input and 300W/48V output.
作者
周国华
范先焱
许多
吴松荣
ZHOU Guo-hua;FAN Xian-yan;XU Duo;WU Song-rong(College of Electrical Engineering,Southwest Jiaotong University,Chengdu 611756,China)
出处
《电机与控制学报》
EI
CSCD
北大核心
2020年第10期9-18,共10页
Electric Machines and Control
基金
国家自然科学基金(61771405)
四川省科技计划(2019JDTD0003)
中央高校基本科研业务费专项资金(2682019YQ02)。
关键词
LLC谐振变换器
移相控制
宽范围电压输入
定频控制
状态平面轨迹
混合模式
软开关
LLC resonant converter
phase shift control
wide input voltage range
fixed frequency control
state plane trajectory
hybrid mode
soft switch
