Dual-active bridge dc-dc converter systems for medium-voltage DC distribution grids

Electrical energy distribution with dc grids reduces the investment costs of the system and increases the overall efficiency. For interconnecting different dc distribution grids as well as linkage to transmission networks and integration of renewable energy sources, the dual-active bridge (DAB) dc-dc converter system is a promising topology. Modularity and scalability improve production and reduce maintenance costs. Moreover, redundancy can be implemented easily. Furthermore, high efficiency and high-dynamic controllability ensure a good performance within grid applications. This paper presents the modular DAB converter system and its application for different voltage and power levels. The implementation of redundancy and the transient system behavior during failure will be discussed in addition.