针对LLC谐振变换器宽范围高效率输出的研究与设计  

Research and Design of Wide-range and High-efficiency Output For LLCResonant Converter

作　　者：肖康 陈威[1] 许海波[1] 林振权[1] 孙永乐 Xiao Kang;Chen Wei;Xu Haibo;Lin Zhenquan;Sun Yongle(College of Electrical and Electronic Engineering,Wenzhou University,Wenzhou 10351,China)

机构地区：[1]温州大学电气与电子工程学院,浙江温州325035

出　　处：《机电工程技术》2025年第3期138-147,169,共11页Mechanical & Electrical Engineering Technology

基　　金：温州市重大科技创新攻关项目(ZG2022002,ZG2023032)。

摘　　要：传统LLC谐振变换器只有工作频率在谐振频率点附近时才能实现软开关,而输出电压的调节需要靠调节工作频率实现,一旦输出电压范围较宽就会导致LLC谐振变换器失去软开关特性,所以软开关特性与输出电压宽范围往往不可兼得。提出一种LLCBUCK变换器,该变换器采用LLC电路与BUCK电路并联输入,串联输出的方式,并且LLC电路采用开环控制,工作频率为谐振频率,BUCK电路采用PI闭环控制。此法把LLC电路的强带载能力以及BUCK电路的宽调压能力相结合。在MATLAB中搭建仿真平台进行仿真并与传统LLC谐振变换器进行对比,并试制了一台输入电压60 V,输出电压可以在12~36 V范围内调节,最大输出功率500 W的样机进行实验验证。在仿真实验中LLC-BUCK变换器相比传统LLC谐振变换器电压输出范围提高了2倍,且在相同输出电压下工作效率均超过传统LLC谐振变换器,样机实验结果与仿真实验基本拟合。对样机的工作效率进行测试,发现输出电压为12 V时样机效率最高,为96.7%,输出电压为36 V时效率最低,为88.3%。仿真与样机实验验证了所提出的LLC-BUCK变换器可以实现宽范围电压输出与高效率的特性。Traditional LLC resonant converters can only achieve soft switching when the operating frequency is near the resonant frequency point,and the adjustment of output voltage needs to be achieved by adjusting the operating frequency.Once the output voltage range is wide,it will cause the LLC resonant converter to lose its soft switching characteristics.Therefore,the soft switching characteristics and the wide range of output voltage often cannot be achieved simultaneously.An LLC BUCK converter is proposed,which adopts a parallel input and series output method of LLC circuit and BUCK circuit,and the LLC circuit adopts open-loop control with resonant frequency as the operating frequency.The BUCK circuit adopts PI closed-loop control.This method combines the strong load capacity of LLC circuits with the wide voltage regulation ability of BUCK circuits.Simulation platform is built in MATLAB for simulation experiments and compares it with traditional LLC resonant converters.A prototype with 60 V input voltage,12~36 V adjustable output voltage and a maximum output power of 500 W is made,tests are carried out on the prototype.Simulation results show that,the LLC-BUCK converter has a voltage output range that is twice of the traditional LLC resonant converter,and its operating efficiency is higher than that of the traditional LLC resonant converter under the same output voltage.Test results obtained from the prototype are basically consistent with the simulation.The working efficiency test of the prototype turns out that,the highest efficiency value is 96.7%at output voltage being 12 V.The lowest efficiency value is 88.3%at output voltage being 36 V.Simulation and prototype tests verifies that the LLC-BUCK converter proposed can achieve wide range voltage output and high efficiency.

关 键 词：LLC谐振变换器 LLC-BUCK变换器 软开关 高效率 宽电压输出 PI控制 

分 类 号：TM46[电气工程—电器] TP273[自动化与计算机技术—检测技术与自动化装置]