中文摘要：

提出了一种新型LCL谐振式DC／DC变换器拓扑，它的谐振元件LCL位于Push—Pull电路的输入侧．该Push-Pull变换器的功率开关管工作在占空比固定接近于0．5的非调制模式下，谐振电路频率至少为开关频率的两倍．利用变压器副边励磁电流的续流，变压器原边开关管mosfet工作在接近零电压（ZVS）的条件下．该变换器适用于蓄电池供电的低压大电流输入系统场合．在一台12VDC输入，360VDC输出的直流变换器中的应用试验表明，电路效率达到了92％，试验波形也证明了电路原理分析是正确的．

英文摘要：

The paper presents a new LCL resonant DC/DC converter topology whose resonant LCL components are located in input side of the push-pull converter. The power switch of the push-pull converter operates in fixed nearly duty cycle 0. 5 under unregulated mode. The resonant frequency is more than twice of the switching frequency. The Mosfet primary switches achieve almost zero-voltage switching （ZVS） conditions due to commutation of the magnetizing current of the transformer secondary side. The converter is suitable for the system with low input voltage and large input current input powered by batteries. A converter system with 12 VDC input and 360 VDC output is produced, the test shows efficiency of the proposed front DC-DC achieves 92%. The test waveforms have verified correctness of the theory analysis.