一种零电压开关有源箝位双管正激变换器

Dual switch forward converter with zero voltage switch active clamp

为了解决传统双管正激变换器工作占空比不能大于50%以及零电压开关(ZVS)难于实现的问题,提出了一种ZVS有源箝位双管正激变换器.该变换器在传统双管正激变换器的基础上添加了辅助开关管和饱和电感,利用有源箝位的复位方式使高频变压器的复位条件得到改善.在分析主、辅开关管一个开关周期中工作过程的基础上,得到了变换器各工作阶段的等效电路,并推导了电路关键参数优化选择的约束条件.研究表明,该变换器克服了传统双管正激变换器的缺点.适用于宽输入电压范围的场合.变换器的变压器磁芯的复位电压可以大于输入电压,所有的开关管都实现了ZVS,在不同的负载条件下变换器都达到了较高的转换效率.

To resolve the problems that the duty cycle of conventional dual switch forward converter cannot be more than 50% and that zero voltage switch （ZVS） is hard to achieve, a new dual switch forward converter ZVSactive clamp was presented. Auxiliary switches and a saturable inductor were added to the conventional dual switch forward converter. By utilizing the active clamp reset scheme, the reset condition of the high frequency transformer was improved. Through analyzing the operating process of the main switch and the auxiliary switch during a switching period, the equivalent circuit for each working stage was obtained and the restrain conditions for choosing key parameter were derived. Experimental results show that the new converter can overcome the disadvantage of conventional dual switch forward converter and is suitable for working on much wider input voltage range. The converter＇s reset voltage of the transformer core can be higher than the input voltage, all of the switches＇ ZVS can be achieved and the conversion efficiency is improved under different load conditions.