Comparison among Two-Phase Three-Wire AC Off-Grid Power Systems

The update of the power system moves over to connection of small distributed energy resource through grid-interactive converters. The electrifying process of the distribution power system allows the implementation of different grid configurations, such as those based on two-phase three-wire systems that are appealing for residential zones, commercial areas and off-grid systems. The off-grid two-phase three-wire topology can be implemented considering voltages as an extension of the conventional three-phase system (abn), voltages in quadrature (αβn), or voltages with opposite phases (xyn). Then, this paper aims at comparing the three off-grid power system topologies in terms of power quality characteristics, sizing of DC capacitor of grid-connected inverters, sizing of neutral conductor, and integration with the conventional mains. To accomplish those goals, a mathematical approach considering the Conservative Power Theory and computational simulations are shown and discussed.