Harmonic and electromagnetic interference (EMI) filters are the two important parts in the grid-connected inverter for the harmonic and EMI noise suppression. This article investigates the combined magnetic integration of the harmonic and EMI filters with the volume and weight reduction, which is defined as the integrated LCL-EMI filter in this article. Both common-mode (CM) and differential-mode (DM) models of the integrated inductor with EE-type magnetic core are built and analyzed. By designing the air gap of the center leg and arranging the windings properly, the distribution of magnetic flux on the magnetic branch can be controlled. As a result, harmonic inductors and a CM inductor can be effectively designed in the center leg and side leg, respectively. A symmetrical LCL filter is designed instead of the traditional asymmetrical structure with an integrated magnetic core. The current harmonic distortion analysis and EMI measurement results based on simulation and experiment results verify the effectiveness of the proposed integration method in the silicon carbide (SiC) MOSFET-based grid-connected inverter. Moreover, weight and volume comparisons between the integrated inductor and the traditional discrete inductors also reflect the superiority of the magnetic integrated LCL-EMI filter.

中文翻译：

---

用于单相SiC-MOSFET并网逆变器的磁集成LCL-EMI滤波器

谐波和电磁干扰（EMI）滤波器是并网逆变器中抑制谐波和EMI噪声的两个重要部分。本文研究了谐波滤波器和EMI滤波器在减小体积和重量上的组合磁集成，在本文中将其定义为集成LCL-EMI滤波器。建立并分析了具有EE型磁芯的集成电感器的共模（CM）和差模（DM）模型。通过设计中腿的气隙并适当地布置绕组，可以控制磁通在磁分支上的分布。结果，可以分别在中脚和侧脚有效地设计谐波电感器和共模电感器。设计了对称的LCL滤波器，以代替具有集成磁芯的传统不对称结构。基于仿真和实验结果的电流谐波失真分析和EMI测量结果证明了该集成方法在基于碳化硅（SiC）MOSFET的并网逆变器中的有效性。此外，集成电感器和传统分立电感器之间的重量和体积比较也反映出集成的磁性LCL-EMI滤波器的优越性。