一种兼具屏蔽效能的变压器平衡绕组技术

A Transformer Balance Winding Technology With Shielding Effectiveness

针对现有绕线式变压器平衡绕组方案需多次试错调整、且难以兼顾电磁干扰(electromagnetic interference,EMI)特性和电气性能的问题,文中分析平衡绕组设计存在误差的原因,提出一种兼具屏蔽作用的平衡绕组技术,通过加入结构简单且容易实施的改进型平衡绕组,能够有效地抑制反激变换器在传导干扰频段的共模噪声。文中定量地分析变压器传输路径上完全消除共模位移电流的机理,给出改进型平衡绕组的设计准则。实验结果表明,在变压器绕组交错排布的情况下,只需在变压器中加入一层兼具屏蔽作用的平衡绕组,即可达到显著的共模干扰抑制效果,有效降低了变压器EMI特性优化设计的实施难度。

To solve the problem that the traditional balance winding schemes require multiple trial and error adjustments,and the EMI design and electrical performance of transformers usually can’t be satisfied altogether. This paper worked on the transformer with spiral windings. The causes of errors in the traditional balance winding design were analyzed and a balance winding technology with the shielding effectiveness was proposed, which could be achieved by adding a simple structure and easy implement improved balance winding to suppress the common-mode(CM) conducted noise of the flyback converter effectively. The mechanism of eliminating the CM displacement current on the transformer transmission path was quantitatively analyzed, and the design criteria of improved balance winding were proposed. Experimental results show that under the condition that the transformer windings are interleaved, the improved balance winding only needs to occupy one-layer winding space of the transformer, and it can achieve the lowest CM interference amplitude. The manufacturing process of transformers in the EMI optimization design is effectively simplified.