LLC谐振变流器最小工作频率的计算方法  

Calculation Method of Minimum Switching Frequency for LLC Resonant Converter

作　　者：徐恒山[1] 黄永章[1] 

机构地区：[1]华北电力大学新能源电力系统国家重点实验室,北京102206

出　　处：《华北电力大学学报（自然科学版）》2017年第4期29-36,共8页Journal of North China Electric Power University：Natural Science Edition

基　　金：国家重点研发计划项目(2016YFB0101901)

摘　　要：将LLC谐振变流器用于车载充电机(On-Board Charger,OBC)的高频隔离DC/DC。全负载范围内,LLC谐振变流器的原边开关器件实现零电压开关(Zero Voltage Switching,ZVS),副边整流二极管实现零电流开关(Zero Current Switching,ZCS)。考虑输出电压变化时LLC谐振变流器的品质因数也随之变化,以轻载和重载的品质因数为边界条件,计算出LLC谐振变流器的最小工作频率,避免了传统基波近似法不能得到LLC谐振变流器最小工作频率的缺点并为LLC谐振变流器的磁件设计提供理论支持。最终研制了一台3.3k W OBC样机,其功率密度达到1.05 k W/L,整机峰值效率达到95.01%,LLC谐振变流器的峰值效率达到97.4%。LLC resonant converter is utilized in on-board charger＇ s DC/DC converters with high-frequency isolation of on-board charger （OBC）. Within full load output voltage range, primary switching device and secondary rectifier diodes of LLC converter achieve zero-voltage switching （ZVS） and zero-current switching （ZCS） , respectively. Considering the LLC resonant converter＇ s quality factors varying with changing output voltage, take power quality factors of light load and heavy load as critical boundary conditions to figure out the minimum switching frequency of LLC resonant converter. It avoids the disadvantage that traditional fundamental wave approximation is unable to calculate minimum switching frequency of LLC resonant converter and also provides theoretical support for magnetic components designing magnetic components of LLC resonant converter. Eventually, a 3.3 kW prototype with power density of 1.05 kW/L and peak efficiency of 95.01% is developed. Peak efficiency of LLC resonant converter can reach 97.4%.

关 键 词：车载充电机 交错功率因数矫正器 LLC谐振变流器 品质因数 电压增益 

分 类 号：TM131.4[电气工程—电工理论与新技术]