Accurate Analysis of Core Loss Considering the Non-uniform Magnetic Flux Distribution for High-Frequency-Transformer in Dual-Active-Bridge DC-DC Converter

Accurate core loss estimation is essential for efficiency evaluation and optimal design of high frequency transformers (HFT). The accurate analysis of magnetic flux distribution and flux density waveform is the first step in accurate prediction of magnetic core loss. Traditionally, the triangular or trapezoidal waveforms are supposed as the practical flux density waveforms. In this paper, an accurate analysis of magnetic flux distribution and core loss for high-frequency-transformer (HFT) in dual-active-bridge (DAB) converter is conducted. Firstly, the non-uniform flux distribution is analyzed. The finite-element-method (FEM) is used to calculate the non-uniform flux density distribution. Secondly, the influencing factors of practical flux density distribution are discussed. Finally, the core loss calculation errors with or without considering the practical flux density distribution are compared. The proposed practical flux density distribution analysis can contribute to accurate core loss estimation of HFT.