针对推挽DC/DC变换器,随输出功率增加,开关管关断时次级漏感引起MOSFET尖峰增加,同时MOSFET开通损耗加大.提出一种双变压器LC串联谐振软开关电路,两个变压器采用初级绕组并联,次级绕组串联,实现LC串联谐振软开关,实现MOSFET在零电压下开通或零电流下关断,从而降低开关管导通与关断时漏感引起的尖峰.制作48 V输入、380 V直流输出的3 kW的DC/DC LC串联谐振变换器.实验证明,串联谐振电路可以大幅度减小MOSFET开通与关闭时漏感引起的尖峰值.%For Push-Pull DC-DC converter,as the power increases,the Vds voltage spike in between drain to source caused by the secondary winding inductance leakage increases as well,and the MOSFET power loss increases too. In order to cut down the Vds spike,a double transformer LC series resonant soft-switching circuit is proposed. The two transformers in the double transformer parallel in their primary sides and series in their secondary sides,achieve LC series resonant soft-switching,the MOSFETs turn on when the Vds voltage decrease to zero,even called zero-voltage-switching,or as the current decrease to zero these MOSFETs turn off,even called zero-current-switching,then,the Vds spike reduces caused by the transformers' secondary winding inductance leakage when the MOSFETs turn on or turn off decreased. A 3 kW DC-DC LC series resonant converter has been made,and the input is DC 48 V and the output is DC 380 V. According to the experience,the spike of MOSFETs' Vds caused by inductance leakage is cut down drastically. The experimental results show the LC series resonant soft-switching converter can cut down the spike of MOSFETs drastically.
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