Peak Flux Density Reduction in Dual Active Bridge Converters

Abstract

The flux density in Dual Active Bridge (DAB) converters plays a crucial role in designing a high-power density converter, especially in applications requiring compact and lightweight designs. Symmetric Unipolar Modulation (SUM) not only doubles the transformer frequency to 2fsw without increasing the switching frequency (fsw) of the semiconductor devices, but it modifies the flux density in the core from triangular (conventional modulation) to trapezoidal while reducing its peak. The trapezoidal flux density in SUM significantly reduces the peak flux density requirement, thereby reducing the core size compared to traditional modulation. Simulation and experimental results validate these findings, highlighting SUM's potential for achieving higher power density in DAB converters. © 2025 IEEE.