Dual Active Bridge dedicated to DC-DC conversion

This article presents a detailed study of the Dual Active Bridge (DAB) converter. Within DC-DC conversion, this is a topology associating a source and a load of a capacitive nature. As a result, it has an inductive element, which will be the key factor in sizing.

This structure is enjoying renewed interest, not only because of the performance it can achieve, but also because of its bidirectionality. A detailed study of the simplest control mode, commonly known as phase-shift, identifies all the main characteristics and establishes the constraints on power components (active and passive) with a view to their sizing.

The presence of two inverters in a bridge configuration offers numerous control options, which are analyzed with a view to improving efficiency. The first harmonic method is used to simplify the approach and establish trends. Based on these trends, accurate modeling is carried out to propose optimal modulation.

Extensions to this converter are then presented. In particular, the series-resonant DAB converter displays resonance-related peculiarities, and two methods of dimensioning the resonant circuit are proposed. Variants are also discussed, with a view to the realization of direct AC-DC converters and the connection of three DC networks, useful when a storage medium is to be associated.

At the end of the article, readers will find a glossary and table of acronyms and symbols.