Optimum design of high frequency transformer for compact and light weight switch mode power supplies (SMPS)

In this paper a new approach for optimization of high frequency transformer design is presented. The presented design method is based on a restatement of the traditional transformer design equations to include non-sinusoidal switching waveforms and high frequency skin and proximity effects. In this optimization procedure both electric and thermal effects in the transformer is considered. Wave form of voltage and current, and maximum acceptable temperature rise, are used as input data. The aim of this procedure is the selection of the smallest core that can deliver desired power, and determination of optimum flux density and current density to reach a transformer with high power density and admissible temperature rise. Since the transformer is the major contributor to the volume and weight of the Power Supply, the results of this transformer analysis can be used for entire power supply optimization as well. Finally the validity of presented method is analyzed.