A Bidirectional DC-DC Converter to Interlink Unipolar and Bipolar DC Microgrids

DC microgrids are starting to become quite important in the actual context of electrical energy distribution grids. There are two main structures for these grids, the unipolar and the bipolar DC microgrids. In this paper, a DC-DC converter that allows to interlink these two DC microgrids is proposed. This converter is a non-isolated bidirectional DC-DC converter with bipolar and unipolar interfaces. The converter was designed to transfer energy between these microgrids and, at the same time, to support the balance of the bipolar DC microgrid. Moreover, the proposed converter is also able to operate as a standalone voltage balancer to support the bipolar DC microgrid. The converter also presents bidirectional buck-boost characteristics. Simulations and experimental results of the DC-DC converter operating in both directions will be provided. From the presented results, it will be possible to verify the capability of the converter to operate as interlink interface for both microgrids.