FEA Based Transformer Loss Analysis for Dual Active Bridge DC–DC Converter Using Triple Phase Shift Modulation

High-frequency transformers are a key component of dual active bridge (DAB) dc–dc converters, providing isolation and voltage scaling. The losses in the transformer should be minimized to improve efficiency and extend lifetime. The existing research focuses on the optimization of design parameters, such as core material, cross-sectional area and winding configuration to minimize losses. However, the transformer losses also depend on the harmonic content of the current as well as the design parameters and thus the efficiency can be further improved by selecting a modulation scheme which results in minimum current harmonics. This article evaluates the effect of modulation schemes on the transformer losses of a DAB converter operating under triple phase shift (TPS) modulation using finite element analysis. A comparison of losses under different modes of TPS modulation has been provided and it is proven that losses can be significantly reduced by selecting optimal modulation schemes. The experimental results performed on a 1-kW DAB converter laboratory prototype are provided to validate the proposed work. Moreover, a generalized framework has been proposed to analyze and optimize transformer losses for isolated converters.