Double Active Bridge Operated in Quasi Discontinuous Conduction Mode

The quasi discontinuous conduction mode (QDCM) of the double active bridge (DAB) is addressed in this paper. The DAB converter usually is operated turning on always two semiconductors per bridge, and this leads to a continuous inductor current: However, a similar operation to dc/dc converters can be implemented, for this, less than two switches are turned on, at certain time, in one of the bridges; this leads to the quasi-DCM. With this mode of operation, a natural soft-switching is performed during the whole range of operation, but also low current stress is performed compared to the square modulation, not only at low power range. The modulation is relatively simple compared to other techniques. The proposed technique is described, analyzed, numerically simulated, and experimentally tested.