Seminar Description: This tutorial is devoted to the state-of-the-art dc microgrids, their structure, challenges and perspectives. First of all, possible architectures of dc microgrids, along with standardization efforts, will be discussed. The key power electronics topologies used as bidirectional interface converters between ac and dc parts will be reviewed, followed by the state of the art in dc microgrid protection and grounding approaches. Due to the absence of zero-current crossing, an arc that appears upon breaking dc current cannot be extinguished naturally, making the protection of dc microgrids a challenging problem. Concerning this, a comprehensive overview of protection schemes will be provided along with the design of practical protective devices and their integration into overall protection systems. Main features of control structure of dc microgrids will be explained and categorized with special focus on the droop control. Real cases of residential DC microgrids and DC buildings will be presented.
Finally, the prospects, main challenges, research gaps, trends in the dc microgrid architectures, hidden advantages, and nearest implementation fields will be reviewed and summarized.
