DC Microgrid: State of Art, Driving Force, Challenges and Perspectives

The chapter is devoted to the state-of-the-art dc microgrids, its structure, challenges and perspectives. First of all, possible structures of dc microgrid along with standardization process are revealed. An overview of the state of the art in dc microgrid protection and grounding is provided. 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. In relation with this, a comprehensive overview of protection schemes, which discusses both design of practical protective devices and their integration into overall protection systems will be in focus. The key power electronics topologies are used as bidirectional interface converters between ac and dc parts will be disclosed. Main features of control structure of dc microgrids will be explained and categorized. Finally, the prospects, main challenges, research gaps, and the trend of the dc microgrid structures and control will be reviewed and summarized in the conclusions.