一种全波整流有源箝位ZVS正激变换器的研究

介绍了一种中心抽头全波整流有源箝位ZVS正激变换器的工作原理及主要参数计算。有源箝位电路由一个箝位开关管和箝位电容组成。变压器磁芯实现无损复位,励磁能量和漏感能量全部传递到负载,磁芯利用率高,功率开关管承受电压应力降低。通过变压器漏感与开关管输出电容的谐振,主开关管与箝位开关管都可以实现ZVS开通,提高了变换器工作效率。首先分析了变换器工作原理,然后给出了主要参数的计算方法,最后通过样机(48V输入,5V/20A输出)实验验证了该拓扑的高效性能。

Research on an Active Clamp ZVS Forward Converter Based on Full-wave Rectifier

An active clamp ZVS forward converter based on center-tapped rectifier was introduced.The steady-state operation analysis and the key parameters are given in detail.By the active clamp circuit which is composed of the auxiliary switch and the clamp capacitor,the energy stored in the transformer leakage can be transferred to the second winding side,the peak voltage of the transformer is minimized.Therefore the voltage stress of the main switch can be reduced.By the resonate circuit based on the leakage inductance of the transformer and output capacitor of switches, both of the main and auxiliary switches can operate at ZVS hence the total circuit efficiency can be increased.The circuit operation and mathematical analysis are discussed at first,the key parameters are calculated,finally a sample with 5V/20A output load demonstrates the performance characteristics of the active clamp ZVS forward converter.