Predicting parasitics and inductive coupling in EMI-filters

The challenge of EMC is a crucial aspect regarding the reliability of power electronic applications. State-of-the-art in assuring EMC in the radio frequency range are low-pass-filters with passive components. The nowadays filter design is characterized by a trial-and-error-process which is the more efficient the more experienced the designer is. An accurate prediction of EMI-filters´ insertion loss requires the correct calculation of mutual coupling between the circuits´ components as well as of the components parasitics. It does need some experience to define crucial points of coupling and it would be best to calculate them by a field solver like the PEEC-method, which has become state-of-the-art in high speed chip design. In this paper it is shown that the prediction of EMI-filter performance can be improved by implementing coupling calculation on the basis of simple formulas, when using a field solver is not wanted