Finite element model of a foil wound choke

Foil wound chokes are often used as output filters for switch mode power supplies. The component of current is DC, however the principle loss component is at the switching frequency (20-100 kHz). These losses are notoriously difficult to estimate especially when there is a significant air gap gap in the core. The authors present a finite element solution for estimating the AC power losses in such devices. The low frequency subset of Maxwell´s equations are used (that is capacitance is neglected). They assume that there are no losses in the ferrite core to reduce the size of problem to be solved