Improved thermal design of a high frequency power transformer

In this paper the thermal management of a high frequency power transformer is investigated. To begin with, it is shown how the total power loss of such a device can be easily predicted. Based on the results, the temperature distribution inside the transformer is simulated. It is demonstrated how different cooling conditions affect the hot-spot temperature. Copper coil formers to improve the thermal connection between coil/core and the bottom plate of the transformer are presented. Further, the effect of insulation material with improved thermal conductivity is investigated. Different transformer prototypes were realized to illustrate the practical capability of the applied thermal model. All simulation is based on finite element method (FEM) and verified by means of experimental data drawn from various electrical and thermal measurements.