Experimental Evaluation of a Dual DC Buses Nanogrid with Interlink Converter

Abstract

Due to the increasing addition of distributed energy resources (DERs) on residential and commercial buildings, nanogrids have been considered for low voltage and low power installations. In this application, extra-low voltage dc buses are interesting to supply different loads with reduced power processing stages. This is because many loads and sources can be easily integrated on extra-low voltage dc buses (ELVDC), as well as batteries, electronic loads, PV panels, and others. On the other hand, the highest voltage levels dc buses are still important to allow the ac grid connection. To form nanogrids with more than one dc bus, the development of bidirectional interlink converters (BIC) is important and is still a challenge due to the wide voltage rations between ELVDC and LVDC buses. A Current-fed Dual-Active Bridge (CF -DAB) converter is proposed in this paper to evaluate experimentally a dual buses nanogrid. In addition, a control structure and an average model are presented to perform the closed-loop results.