Compact Modeling of Thermal Properties of Selected Planar Transformers with Ferrite Cores

This paper presents the results of modeling and measuring the thermal properties of selected planar transformer designs. A compact thermal model for the steady state of the planar transformer is presented. A method for measuring its parameters is discussed. The investigation results, illustrating the practical usefulness of the considered thermal model for describing the thermal properties of transformers containing ferrite cores made of different materials, are presented and discussed. The influence of the transformer’s operating frequency and load resistance on the temperatures of each component of the tested transformers is discussed. It is demonstrated that the proposed model enables the correct determination of these steady-state temperatures over a wide range of operating conditions for transformers with cores made of different ferrite materials.