Inductive, Capacitive and Resistive Aspects Modeling of Planar Windings Applied to a 1 MHz LLC Converter

Planar transformers and inductors are subject to parasitic capacitances that can alter the operation of the converter using them. This article integrates capacitive aspects into conventional inductive and resistive modeling developed by Dowell [1]. This leads to a relatively simple software program that enables fast simulation of planar components’ frequency behavior, predicts conductors’ current distribution, and deducts the resulting losses. Finally, an application example is proposed consisting of optimizing the design of a transformer by adjusting its windings, the nature of its materials, and the position of an air gap, to minimize current oscillations in the converter that could result from excessive parasitic capacitors.