开关电源高频平面变压器并联PCB线圈交流损耗建模及分析

AC Loss Modeling and Analysis For Parallel PCB Winding in High-frequency Power Planar Transformer

并联PCB线圈可很好克服厚导体交流损耗大的不足,提高高频平面变压器的载流能力,但由于并联PCB线圈并联层间特有的环流效应,线圈设计变得十分复杂。通过建立并联PCB线圈交流损耗模型,对并联层间环流的产生机理及影响因素进行了深入分析。结果表明,电流频率、原副边线圈交叉换位与组内线圈交错、PCB厚度以及绝缘层厚度等对环流/线圈交流损耗均有很大影响。分析结果和系统化实现的模型为设计提供了方法和指导。实验验证了损耗模型的正确性。

PCB winding with parallel connection is a good solution to improve current handling capability of highfrequency power planar transformer. However, uneven current sharing among paralleled PCB layers caused by circumtluent current imposes severe challenges on the winding design. The mechanism and factors affecting the current sharing are analyzed deeply and thoroughly with AC eddy loss model built. The results show that exciting current frequency, PCB trace layout, trace connection schemes, thickness of traces and insulation of parallel PCB winding all have great effects on the winding loss. The design guidelines for parallel PCB winding and systematic programming technique for the loss model are also given. Loss model is verified by the experiments.