Comparative Analysis of Buck-Boost Topologies Integrated with 3ph-DAB for Wide-Range DC-DC Conversion in Electric Vehicles

The shift toward electrifying medium- and heavyduty vehicles is crucial for cutting greenhouse gas emissions and preserving non-renewable energy sources. This research proposes a design strategy for high-efficiency DC-DC converters in electric vehicles, targeting a wide input voltage range of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$400 \mathrm{V}-850 \mathrm{V}$</tex> and a 56 V output at 20 kW. The three-phase dual active bridge (3ph-DAB) converter, while efficient at nominal conditions, faces challenges with increased losses and electromagnetic interference (EMI) at low input voltages at rated power, as identified in literature. To address this, the study integrates a four-switch buck-boost (FSBB) stage with the 3ph-DAB to mitigate softswitching losses, conduction losses, and EMI. A detailed evaluation of multiphase interleaved FSBB configurations and an energy-storage-based inductor selection approach is conducted. LTSPICE simulations validate the effectiveness of the proposed solution, supporting the selection of the 3 -phase topology as the optimal design variant for performance, despite higher costs, while the 1-phase variant offers a cost-effective alternative.