  The integration of single-phase distributed generations (DG) and unbalanced
loads to three-phase DGs brings challenges to the operating system of the
microgrids (MGs). These challenges include unbalanced voltage and unequal power
flow at the point of common coupling (PCC) of the MGs. The aim of this paper is
to develop an Energy Storage System (ESS) with multi-function control for
islanded multi-microgrids (MMG) consisting of single and three PV-DGs to
enhance its power quality and power-sharing of the MMGs. The proposed
multi-function control consists of a reactive power compensation (RPC), a PCC
power balance regulator (PBR), and a reactive power sharing algorithm (RPSA).
The RPC and the PBR improve the three-phase PCC voltage and power unbalance of
the MMG and the RPSA regulates the reactive power-sharing among the MMGs. The
proposed strategy is experimentally validated on the Opal-RT OP5600 real-time
simulator. The voltage unbalance factor (VUF) at the PCC is reduced from 4.3
percent to 0.03 percent, while the three-phase and the single-phase reactive
powers are shared proportionally between different rated DGs.
