Design Guidelines for a Dual Active Bridge Converter Incorporating a Multilevel Bridge with Quasi-2-Level Operation

Abstract

The development of medium voltage DC networks requires efficient DC-DC converters. In this context, the Dual Active Bridge (DAB) with quasi-2-level (Q2L) operation is analyzed as a potential candidate. Power transfer equations, conduction losses and zero voltage switching conditions are derived using Fourier series approximations. Operating principles for multilevel converters are also provided. It is determined that 25° is the boundary of the transition time at which 2L design equations remain valid for Q2L operation. Furthermore, Q2L operation demonstrates superior efficiency during medium to high load operation, due to reduced switching losses, provided the transition time is chosen optimally.

Jose Andres Aguilar Croston, Jean-Yves Gauthier, Cyril Buttay, Maryam Saeedifard, Besar Asllani, Piotr Dworakowski

Presented at EPE 2025