双有源桥DC-DC变换器传导干扰分析

Analysis of Conducted EMI for Dual Active Bridge DC-DC Converter

电力电子变压器中广泛采用双有源桥(DAB)DC-DC变换器结构,电磁干扰现象复杂,针对其传导干扰内在机理的研究较少。对此,文章首先针对线性阻抗稳定网络(LISN),仿真分析了其在不同位置时测量结果所呈现的差异;之后,针对开关管数量较多、对地寄生电容较复杂不利于分析的问题,提出了在不同时刻分别考虑左右全桥对地电容的方法,并借助建立部分单元等效电路来依次分析其共模和差模干扰产生的机理,结合时域和频域内的仿真进行验证;最后,对整个电路的传导干扰进行综合分析,指出左右全桥对地电容对传导干扰的影响及存在的差异。

Electromagnetic interference phenomenon in dual active bridge （DAB） DC/DC converter which is widely used in power electronic transformer is complicated, and there has been lack of the relevant research on its internal mechanism. Aiming at line impedance stabilization network （LISN）, this paper firstly analyzed the difference in measurement results caused by different positions of LISN. Then considering the number of switch and ground parasitic capacitance in DAB, which increases the difficulty of research, a new method analyzing the ground parasitic capacitances in left and right bridge respectively in different time was proposed, and through establishing partial element equivalent circuit, the producing mechanism of common and differential mode was revealed successively. Results were proved by simulation both in time and frequency domain, and finally the conducted interference of whole system was analyzed comprehensively, the impact on conducted interference caused by ground parasitic capacitances in left and right bridge and its difference were pointed out.