Influence of selected factors on the parameters of a compact thermal model of an air transformer

The paper proposes a thermal model of an air transformer used in wireless power transfer (WPT) systems. This model takes into account self-heating in each of the windings and mutual thermal couplings between the windings. The description of the model takes into account the influence of the power dissipated in each of the windings and the distance between the windings on their self and transfer transient thermal impedances. The form of the proposed model, the method of determining its parameters, and the results of the model correctness verification on the example of a transformer with ring-shaped windings are presented. A good agreement was obtained between the results of measurements and simulations.