Experimental Investigation of Inter-Phase Power Management in Residential Microgrids

Abstract

With increased installation of single-phase rooftop PV systems, in-house battery storages, and high-power plug-in loads (i.e. EVs) at single-phase residential sites, it is prevalent that more and more distribution systems are becoming severely unbalanced causing power quality problems and thermal risks at distribution substations. To solve this problem, two main strategies have been developed previously by the authors, known as intra- and inter-phase power management strategies. The latter makes use of interconnecting back-to-back converters between the phases to mitigate the phase imbalance caused by the various single-phase DG units and loads. This paper devotes laboratory evaluation of the developed schemes and demonstrate key features experimentally on inter-phase power management. Two main experiments have been carried out to confirm that the developed technique can use the surplus power capacity from one phase to support the load demand in another phase to achieve dynamic power balance. From the point view of the substation transformer, the three-phases will always appear to be balanced despite the fact that different phases can have very different local generation and load profiles.

Keywords

• Single-phase microgrids
• inter-phase power management
• unbalanced systems
• back-to-back converter