Identification and improvement of stray coupling effect in an L-C-L common mode EMI filter

作     者：Junping He Wei Chen Jianguo Jiang Shenzhen graduate school Harbin Institute of Technology /Shenzhen P.R. China Delta Electronics (Shanghai) CO.LTD /Shanghai P.R. China Tsinghua University/Beijing P.R. China 

会议名称：《CES/IEEE 5th International Power Electronics and Motion Control Conference》

会议日期：2006年

学科分类：080902[工学-电路与系统] 0809[工学-电子科学与技术（可授工学、理学学位）] 08[工学] 

关 键 词：stray electromagnetic coupling parasitic parameter EMI filter insertion loss equivalent parallel capacitance 

摘      要：正the high frequency attenuation performance of an EMI filter is often deteriorated greatly by the stray electromagnetic field existing in interior or exterior of a filter. In this paper, the stray electromagnetic coupling factors in an EMI common mode filter are investigated by different experiments after theory analysis. A novel metal insulated grids method is proposed to separate electric and magnetic field effect between two CM chokes. The parasitic parameter influence of passive components on insertion loss is also analyzed and compared with stray coupling effect. In the end, a novel equivalent paralleled capacitance decrease design is introduced and validated by experiment. Some coupling restrain methods are introduced in this paper too.