Analytic Design Method Based on Homothetic Shape of Magnetic Cores for High-Frequency Transformers

An analytic formulation dedicated to the design of high-frequency power transformers is presented. This approach is based on the area product, and homothetic core shapes are considered. The temperature increase of the transformer is one of the main input data. Winding losses including the effect of eddy currents are calculated as well as core losses. An original model of magnetic losses valid over a wide frequency range of the common ferrite materials is introduced. The analytic formulation is validated by design examples concerning transformers that have been realized and tested. It is finally applied to study the evolution of power density versus operating frequency or power for different winding configurations or magnetic materials.