高功率密度宽增益CLLC谐振变换器的设计研究

The Design and Study of High Power Density Wide Voltage Range CLLC Converter

设计了一种用于给蓄电池充放电的1 kW CLLC双向谐振变换器,该变换器高压侧为400 V母线,低压侧为蓄电池组,电压变换范围为35～50V。通过采用氮化镓器件和优化设计整个电路,该变换器的谐振频率为500 kHz,功率密度达到6.9 W/cm^3,最高效率达到96.24%。同时,为进一步提高该变换器调压范围,提出一种将移相调制与频率调制相结合的调制策略,该策略解决了谐振网络在空载或轻载环境下难以实现低增益的问题。另外,针对CLLC的双向工作特性及高压侧和低压侧开关管的不同工作特性,提出了一种利用数字信号处理器(DSP)对采集到的电压电流信号进行分析来判断整流管开关时间的同步整流策略,大大简化了电路结构。

A high efficiency high power density wide voltage range 1 kW CLLC resonant converter is designed.The high voltage side is 400 V,while the low voltage side is 35-50 V.By the utilization of gallium nitride device and the optimization of the circuit,the resonant frequency of the converter is set as 500 kHz,and the power density reaches 6.9 W/cm3,and the maximum efficiency reaches 96.24%.Meanwhile,to further widen the voltage range of the converter,a hybrid modulation method which combines the phase shift modulation and frequency modulation is proposed.It helps the resonant tank realize a gain that is lower in light load condition.What ＇ s more, a synchronous rectification method conducted by the digital singal processor（DSP） is introduced which has simplified the structure of circuit.