Loss analysis and optimization of round-wire planar windings for domestic induction heating appliances

In this paper a model of the frequency-dependent resistance in round-wires planar windings is developed. The model is completely analytical and based on the superposition of the different loss effects (DC, skin, and proximity) in the wire. The model also includes the field changes caused in the conductors by the induced currents in the neighbouring conductors. In order to verify the model some tests have been performed, so several inductors were constructed and results with both non-loaded and loaded inductors are compared with theoretical predictions.