Balancing Unit for Proper Characterization of a Modified LISN for Effective EMI Noise Separation

摘要

The compliance with standards calls for proper designed EMI filters. EMI typicallyrncomprises common mode (cm) and differential mode (dm) noise. A systematic optimization of EMIrnfilters requires the knowledge of the contribution and distribution of these two noise sources. Thernpaper discusses different methods that allow the independent measurement of cm and dm noise. Onernsuitable method described in detail integrates the separation set-up into the Line ImpedancernStabilization Network (LISN). However, a correct interpretation of the measured results requires arncharacterization of the unavoidable modal conversion of the complete set-up – i.e. the measured levelrnat the dm output in case of pure cm excitation and vice versa. As shown in this paper, thernimplementation of a standard LISN introduces a high amount of imperfections causing the undesiredrnmodal conversion. Thus, for the first time, this paper describes the characterization of the whole set-uprnincluding the LISN.