新颖软开关谐振复位不对称双管正激变流器

为了克服普通双管正激变流器占空比受限于50%从而影响效率提升和不利于宽范围电压输入的缺点，本文提出了一种采用新颖谐振复位技术的不对称双管正激变流器。和普通双管正激变流器相比，该新颖变流器在保持了低开关电压应力的同时，具有仅在普通PWM控制条件下即能将占空比拓宽至50%以上的能力。并且，在原有变压器结构未作改动的前提下，通过一结构简单同时又成本低廉的辅助电路的增加，该新颖变流器即能在各种工作情况下为所有开关管提供软开关条件。因而，该新颖变流器十分适合应用于高电压、宽范围输入场合以作为高效、高功率密度、低成本的绿色节能电源。在详细描述了该变流器的工作原理和设计思路后，一台具有200-400V宽输入范围，48V/5A输出的适用于通信电源系统，最高转换效率达95.3%的样机验证了该变流器的有效性和实用性

A NOVEL SOFT SWITCHING ASYMMETRICAL DUAL SWITCH FORWARD CONVERTER BASED ON RESONANT RESET TECHNIQUE

To overcome the duty ratio limitation issue existing in dual switch forward converter (DSFC) and improve efficiency, a novel resonant reset asymmetrical DSFC was proposed, which, compared with the former resonant reset DSFCs, maintains the advantage of lowering voltage stress on each switch, at the same time, possesses the merits as duty ratio can exceed 50% and conventional PWM operation capability. In addition, ZVS transition for all switches under all conditions is achieved while the auxiliary circuit is comparatively simple and cost effective: no modification was made on the original transformer component. Therefore, the proposed topology can achieve high power density, lower manufacturing costs and has strong capability for high line and wide range input industrial applications where high efficiency requirement is tense. The detail operation principles, as well as the design considerations, were presented. A prototype aiming at telecom system of 200V-400V input, 48V output, whose highest conversion efficiency is 95.7%, was built to verify the validity and applicability of this topology