集成电容网络型高降压比DC/DC变换器

Integrated Capacitor Network Type DC/DC Converter With High Step-down Ratio

随着数据中心供电系统容量的持续增加,48 V的直流母线电压己成为一种发展趋势,这对二次电源的效率、降压比等提出了新的要求。针对传统高转换比开关变换器降压比与效率无法兼顾的问题,这里分析并设计一种整合开关电容网络型高降压比隔离式DC/DC变换器。通过将串联电容Buck变换器与倍流整流网络结合,变换器具有电压应力低、降压比高、电流应力小的优势。此外,通过对变换器漏感和死区时间的设计能够实现初级开关管的零电压导通,有效降低了变换器的开关损耗。这里对该变换器的工作原理、电压增益、电压应力以及软开关等特性进行了分析,并搭建了一台48 V输入、1.2 V/30 A输出的实验样机,实验结果验证了理论分析的正确性及所提方案的可行性。

As the load capacity of the data center power supply system continues to increase,48 V DC bus voltage has become a development trend,which puts forward new requirements on the efficiency and step-down ratio of the secondary power supply.According to the problems of step-down ratio,efficiency and power density of traditional switching converter with high conversion ratio,an integrated switched-capacitor network-type isolated DC/DC converter by combining the advantages of series-capacitor Buck converter and current-doubler rectifier network is analyzed and designed.The proposed converter has the advantages of lower voltage stress and higher step-down ratio.In addition,ze-ro voltage switching of the primary-side switches can be realized by the design of the leakage inductance and dead time of the converter,which effectively reduces the switching loss of the converter.The operating principle,voltage gain,voltage stress and soft switching characteristics of the converter is analyzed.Finally,an experimental prototype with 48 V input and 1.2 V/30 A output is designed and built,and the experimental results verify the correctness of the theoretical analysis and the feasibility of the proposed solution.