非隔离逆变器交直流侧共模干扰耦合抑制

在非隔离的逆变系统中往往需要在逆变器直流侧和交流侧放置电磁干扰滤波器,以往学者主要是研究直流侧或交流侧滤波器的拓扑结构、参数设计等,但对于交流侧和直流侧EMI滤波器两者之间的耦合作用缺少分析。通过分析共模噪声在两侧EMI滤波器之间的耦合特性,在交流侧采用一种浮地结构的EMI滤波器,改变了共模噪声的流通路径。实验结果表明,该结构能够削弱交直流侧共模EMI滤波器的耦合,使得两侧的EMI滤波器可以达到预期效果;同时,能够增强直流侧和交流侧EMI滤波器的共模衰减能力,有效抑制光伏系统的共模干扰。

Suppression of Common-mode Interference Coupling Between AC and DC Sides of Non-isolated Inverter

In a non-isolated inverter system, it is often necessary to add an electromagnetic interference(EMI) filter to the DC and AC sides of the inverter. In the past, scholars mainly studied the topologies of filters on the DC or AC side, but there is a lack of analysis for the coupling between the EMI filters on the AC and DC sides. In this paper, after the analysis of the coupling characteristics of EMI filters on both sides, a floating ground EMI filter is used on the AC side to change the common-mode noise flow path. Experimental results show that this structure can eliminate the coupling between common-mode EMI filters on the AC and DC sides, so that the EMI filters on both sides can achieve the desired effect. At the same time, the common-mode attenuation capability of EMI filters on the DC and AC sides can be enhanced, and the common-mode interference of the photovoltaic system can be effectively suppressed.