零电压零电流不对称半桥串联混合式直流变换器

提出一种ZVZCS不对称半桥串联混合式直流变换器。该变换器的主开关管的电压应力为输入电压的一半，从而使该变换器非常适合高压输入场合。利用副边的辅助电路在宽负载范围内实现了滞后管的零电流软开关(ZCS)，并克服了以前出现的ZVS半桥串联混合式直流变换器所存在的2个半桥分压不均衡的固有缺点，从而使该类拓扑更加实用。此外，由于实现了ZVZCS，变压器原边环流基本被消除，变换器的效率得到进一步提高。文中详细分析了该变换器的工作原理，阐述了其工作特性，在此基础上设计并制作了1台240W(输出24V/10A)的原理样机，并给出了实验结果。

ZVZCS Asymmetrical Half-Bridges in Series Hybrid DC-DC Converter

A novel zero-voltage and zero-current- switching (ZVZCS) asymmetrical half-bridges in series hybrid DC-DC converter is proposed. Voltage stress of each main switch in this converter is reduced to half of the input voltage, which makes the converter quite suitable for high input voltage applications. The ZCS condition for lagging switches under wide load range is provided by a secondary auxiliary circuit, and an unbalanced-voltage-division flaw which inheres in ZVS half-bridges in series hybrid DC-DC converter is overcome in the proposed converter, consequently the converter is more practical. Furthermore, the ZVZCS converter's efficiency is enhanced owing to its primary circulating current being eliminated basically. The principle and characteristics of the proposed converter is analyzed, and based this a 240W (24V/10A output) experimental prototype is designed and built. The experimental results are presented.