The Frequency Dependence of Resistance in Foil‐Wound Inductors

Foil wound air‐cored inductors are widely used in power electronics applications, and often exhibit power dissipation much greater than can be accounted for by the d.c. resistance. This is shown to be due to non‐uniform current flow. A scaling rule, relating the effects to turns and frequency, is demonstrated. The general principle of equal current sharing can be satisfied in a toroidal system.