On coupling with EMI capacitors

Abstract

So far, methodical design of EMI filters for power electronic applications fails, because coupling among the filters' components is not predicted accurately. A method of calculating coupling with EMI capacitors is presented. The method is verified by experimental results. The presented results prove the possibility of simulating field coupling in circuits including the circuit's components. In particular, when miniaturizing power electronic devices, the calculated coupling among conductors and components must be taken into account to ensure EMC at the system level

Broad-Band Modeling of Passive Power-Supply Filter Structures

“…It leads to the proximity effect and increasing of ohmic losses. Thus, one may describe a film capacitor using an asymptotic model for high frequencies (see [7]). This model applies a perfect conductor instead of the dielectric, which is possible because the capacitive part of the impedance is insignificant in comparison to the inductive part.…”

“…In other words, the behavior of a film capacitors at high frequencies corresponds to a lossy inductor. This model is applied and tested for the calculation of inductive coupling between capacitors by the PEEC method only for high frequencies in [7]. Instead of a large (N may be more than thousand) number of layers the authors [7] used a small number of films connected galvanically as a 3-D grid of thin conductors in the free space.…”

“…The first approach based on the combination of the PEEC and boundary element (BE) methods is published in [14]. This approach applies the conventional PEEC method for the modeling of capacitors and coils as in [7] and represents permeable materials by means of the BE method.…”

“…The couplings are computed using tools for 3-D field simulation and implemented in the filter equivalent circuit as mutual inductances for magnetic couplings and as partial capacitances for electric couplings [10]. For example, the authors [7] have applied the PEEC method [11] for the computation of the mutual inductances between the X-caps and punch grid structures. Analogously, one may extract the equivalent mutual inductances and parasitic capacitances using differential full-wave methods (e.g., FIT or FEM, see [12]).…”

Modeling Method of Stray Magnetic Couplings in an EMC Filter for Power Electronic Devices

“…Stray magnetic couplings used in a filter performance simulation can be obtained from geometry by means of commercial 3D simulation software (8) . Furthermore, effective modeling methods of the relevant components for the 3D simulation have been reported in the past investigations (9) (10) .…”