Energy Management Systems for DC Microgrids

With the application of dc microgrids at different scales and topologies, it is possible to integrate different energy sources (such PV systems, fuel cells and batteries) into the energy mix of a larger system with lower conversion requirements. Moreover, it is much easier and cheaper to convert ac power into dc power which, in turn, helps economic operation of future energy systems. By using dc microgrids, it is also possible to achieve energy savings up to a great extent (~15%) and to improve system reliability by reducing the number of devices required and the total points of failure. The dc architecture also enables cost-effective and green solutions for operation and control of zero-net energy residential/office buildings as well as data centers. However, such optimal performance mainly depends on the proper design and application of EMSs which effectively manage the process of energy production and consumption based on predefined objectives and constraints. There are, definitely, a number of challenges in this regard which have to be suitably addressed. Currently, there is a lack of approved standards and technical codes for dc equipment and distribution networks at low voltage. There is also a lack of approved and recognized dc architectures at low-to-medium voltage levels which in turn necessitates different safety and protection practices in comparison with conventional ac systems. Last but not least, there is a strong need for upgrading the existing infrastructure to accommodate dc systems and interfaces.