An integrated common mode and differential mode transmission line RF-EMI filter

The increasing frequency and shrinking size of power electronic converters present growing RF-EMI challenges. As subsequent research on the integrated differential mode RF-EMI filter, this paper proposes an integrated differential mode (DM) and common mode (CM) RF-EMI filter. The filter has a transmission-line-like structure, incorporating CM and DM filter elements in the busbars. Utilizing the proximity effect, the filter guides the high frequency CM and DM currents into appropriate high damping filter elements and achieves high attenuation. An experimental unit has been constructed and small-signal tests have demonstrated its high damping factor for both CM and DM noise at high frequencies. A distributed model based on multi-conductor transmission structure theory is presented in this paper.