An optimized power management system for an islanded DC microgrid

This paper presents an optimized power management scheme for an islanded dc microgrid (DCMG), which includes a photovoltaic system (PV) as a distributed generator (DG), a backup energy storage system (BESS), electric vehicles (EV), an ac load and dc loads. Conventionally, the DCMGs were required to either be shut down during critical situations of their dc-bus overvoltage, or experienced load curtailment during undervoltage caused by a high mismatch between load demand and generation. To solve this issue, weather forecasting and/or employing more DGs were required which had the drawbacks of complexity, availability of more sources and higher cost. The proposed system in this paper uses an enhanced control strategy for the converter's operation of the integrated PV system. As a result, unlike the conventional power management systems, the stability of the dc-bus voltage can be ensured, particularly during the critical situation of dc-bus overvoltage without a need for shutting down the system, adding complexity and increasing total cost. The proposed power management system is analyzed by different scenarios in MATLAB Simulink. From results, it is found that the proposed optimized energy management provides a robust and stable operation for the dc bus when a BESS/EV assistance is not available.