Battery energy storage effect on AC/DC microgrids efficiency

This paper compares the efficiency of AC and DC microgrids from a new perspective. It studies the effect of adding a battery energy storage on a microgrid efficiency. A new designed Finnish-townhouse building is applied to model the power flow and converter types. Losses related to wirings, converters and discharging of the energy storage are calculated in a minute resolution to enhance the accuracy of the results. Ultimately, efficiency is derived for a range of converters' switching frequencies from 4 to 15 kHz while considering the microgrid possible voltage fluctuations in both AC and DC systems. Results represent higher efficiency in the DC microgrid in both cases with and without the existence of the storage. Furthermore, less discrepancy is obtained in the DC microgrid efficiency when the storage is added comparing to the AC microgrid. Accordingly, switching to DC distribution inside the building concerning the fast developments in power conversion devices seems promising in increasing the efficiency of the power systems.