Optimum Design Approach of High Frequency Transformer: Including the Effects of Eddy Currents

摘要

Design of high frequency transformers and inductors deals mainly with core loss and conductor loss calculation. Steinmetz and Dowell's equations are the most common methods to calculate core loss and copper loss respectively. Existing design techniques of HF transformers like the area product and the core geometry coefficient methods use Steinmetz equation and the DC copper loss formula in the selection of the magnetic core. However, for example in Flyback converters, excitation has a rectangular waveform where the frequency and the duty cycle can have a great effect of the core and copper losses. Considering only DC copper losses and Steinmetz equation which is valid with sinusoidal induction can underestimate or overestimate the magnetic core. The main contribution of this paper is to develop a new design approach of HF transformers. The effects of the frequency and the duty cycle on the selection of the optimum magnetic core are taken into account.