椭圆形平面无源集成EMI滤波器的特性研究

Characteristics Research for Elliptic Planar Passive Integrated EMI Filter

为了减小开关电源的体积,提高功率密度,提出一种椭圆形平面LC线圈结构的平面无源集成电磁干扰EMI(electromagnetic interference)滤波器。通过对矩形、椭圆形平面LC线圈进行有限元仿真,对比其综合因素确定了椭圆形平面LC线圈作为EMI滤波器的基本组成单元,并基于该结构实现了无源集成EMI滤波器。在考虑共模电感的寄生电容和共模电容的寄生电感以及它们的等效电阻情况下,建立了平面无源集成EMI滤波器的高频等效电路模型;利用二端口网络A参数矩阵推导了插入损耗的计算公式。仿真和实验表明了该结构的有效性,以及高频模型和插入损耗公式的正确性。

In order to reduce the size of electromagnetic interference （EMI） filter and improve the power density of switch mode power supplies, the elliptic planar LC coil structure is proposed in this paper. The finite element simulation of the rectangle and elliptic planar LC coil is done. By comparing the simulated results of these two coils, it can be seen that the elliptic planar LC coil may be used as the basic EMI filter unit, as well as planar passive EMI filter. The high- frequency common-mode equivalent circuit model is established taking into account the EPC of common-mode inductor and the ESL of common-mode capacitor and their ESR. The insertion loss formulas are deduced with “A” para- meter matrix of two-port network. The simulation and prototype experiment results are presented showing the effectiveness of the new integrated EMI filter structure and its high-frequency common-mode equivalent circuit model and insertion loss formulas.