Non-isolated three-port DC/DC converter for +-380V DC microgrids

This paper describes a novel topology for a non-isolated three-port DC/DC-converter. Target application is the connection of various sources and loads, e.g. photovoltaic, batteries and fuel cells, to a three-wire, two-phase +-380 VDC microgrid with center-tapped neutral. The DC/DC-converter provides a bidirectional power transfer between the DC microgrid, energy sources or storages. The proposed topology can additionally perform power balancing between the positive and negative phase and thus omitting a second DC/DC-converter for balancing. The extended functionality is achieved by using only one coupled inductor. A prototype DC/DC-converter with a nominal power of 6 kW is introduced which was realized to experimentally verify the proposed topology. Measurement results and performance of this prototype are presented.