一种采用倍流整流电路的ZVS-ZCS三电平DC/DC变换器的研究

三电平DC/DC变换器多采用移相ZVS控制,而常规的移相ZVS控制的变换器,滞后臂较难实现ZVS,同时换流时的环流也会降低变换器的效率.另外,传统的输出全波整流设计,其大电流增加了输出滤波电感和变压器的体积以及整流管上的电压应力,这不利于用在低压大电流输出场合.为此,本文采用倍流整流电路的ZVS-ZCS三电平DC/DC变换器,提出把实现滞后臂ZCS的谐振电容设计在副边的倍流整流电路中,有效地克服了环流的影响和降低整流管的电压应力,同时相应地减小了流过变压器副边和输出滤波电感的电流.理论分析和实验验证了方案的正确性.

Research of a current-double-rectifier zero-voltage and zero-current-switching (ZVZCS) three level DC/DC converter

The phase-shifted ZVS is often used in the three-level DC/DC converter,but for the general phase-shifted ZVS converter,it is difficulty for its lagging-arm switches to realize ZVS,and also the converter's efficiency can be reduced by the circular current in the period of the switches commutating.On the other hand,the larger current of the full-wave rectifier makes the size of filter and transformer increased,and at the same time the stress of the rectifier's diodes is increased.It is not suitable to be used in the occasion of lower DC-voltage and larger current.To overcome those weaknesses,a current-double-rectifier ZVZCS three-level DC/DC converter is proposed in this paper,which realizes zero-voltage-switching for the leading switches and zero-current-switching for the lagging switches,and it is effective to avoid the influence of the circular current,and lower the stress of the rectifier's diodes.For the sake of reduction of the current of the filter inductor and transformer,the current-double rectifier is designed in this ZVZCS three-level DC/DC converter.Both theoretical analysis and experimental results confirm the validity of the proposed design.