Performance Assessment of ISOP LLC with Buck-Boost Post-Regulator and ISOP LLC-DAB

This paper provides a comparative efficiency analysis of two dc-dc topologies—LLC with non-inverting buck-boost post-regulator and LLC-DAB—by evaluating the losses of Gallium Nitride (GaN) HEMTs in both converter topologies. The study considers conduction, switching, gate driver, and reverse conduction losses to ensure a comprehensive comparison. Results demonstrate that the LLC-DAB topology achieves superior efficiency, particularly at full power, due to the Zero-Voltage Switching (ZVS) capability of the DAB stage, which minimizes switching losses and enhances the performance of the LLC modules. In contrast, the LLC with non-inverting buck-boost post-regulator topology exhibits higher efficiency at lower power levels but suffers from increased switching losses at full load due to its hard-switching operation.