电工技术学报2024，Vol.39Issue(8)：2511-2522,12.DOI:10.19595/j.cnki.1000-6753.tces.230147
宽增益高效率CLLLC变换器的变频双移相调制策略
Variable-Frequency Dual-Phase-Shift Modulation Strategy for CLLLC Converter with Wide Voltage Gain and High Efficiency
摘要
Abstract
In the DC microgrid,a bidirectional isolated DC-DC converter with a wide range of input voltage is required to ensure the safety and efficiency of power conversion.The CLLLC converter was selected by discussing the advantages and disadvantages of various DC-DC converters.Aiming at the problem of large secondary switch loss and limited step-down range of variable-frequency phase-shift modulated CLLLC converter,this paper proposes a variable-frequency dual-phase-shift(VF-DPS)modulation strategy.The proposed VF-DPS modulation strategy can enhance the voltage gain and efficiency of the CLLLC converter by simultaneously adjusting the switching frequency,phase-shift angle in the primary side full bridge,and phase-shift angle between the primary and secondary sides. The proposed strategy operates in two modes:the buck mode and the boost mode.In the buck mode,when the input voltage exceeds the rated input voltage,adjustments in the phase-shift angle in the primary side full bridge achieve a voltage gain of less than 1.In the boost mode,when the input voltage is below the rated input voltage,adjustments in the phase-shift angle in the secondary side full bridge result in a voltage gain greater than 1.According to these two modes,VF-DPS modulation is adopted for the CLLLC converter.The waveform shapes of the resonant inductor current and excitation inductor current are changed by VF-DPS modulation,achieving zero voltage switching(ZVS)for all switches.The modal analysis of the VF-DPS modulated CLLLC converter is conducted.Time domain analysis method is used to solve the voltage gain and resonant inductor current.Furthermore,the influence of different frequencies and phase-shift angles on the voltage gain and root mean square of the resonant inductor current is analyzed. An experimental prototype was designed with an input voltage of 100～300 V and an output of 400 W/48V.The experiments tested the wide input range,working mode,soft switching,and efficiency of the CLLLC converter.The peak efficiency is 95.1%in the buck mode and 94.4%in the boost mode,confirming soft switching in both operating modes.The VF-DPS modulated CLLLC converter has a wider gain range and higher efficiency than the variable-frequency phase-shift modulation. The proposed VF-DPS modulated CLLLC converter addresses challenges of wide switching frequency variations and ZVS losses in the wide input voltage of the variable-frequency modulated CLLLC converter and the phase-shift modulated CLLLC converter,respectively.The VF-DPS modulated CLLLC converter realizes the soft switching of all switches.Moreover,the converter achieves a voltage gain range of 3 times and a peak efficiency of 95.1%.Future research will focus on integrated magnetic design to further enhance efficiency and reduce the volume of the converter.关键词
变频双移相调制/宽输入电压/CLLLC变换器/时域分析/零电压导通Key words
Variable-frequency dual-phase-shift modulation/wide input voltage/CLLLC converter/time domain analysis/zero voltage switching分类
信息技术与安全科学引用本文复制引用
周国华,王淇,邓伦博..宽增益高效率CLLLC变换器的变频双移相调制策略[J].电工技术学报,2024,39(8):2511-2522,12.基金项目
国家自然科学基金资助项目(62271417). （62271417）
