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 aswell 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.