Grid-Forming Three-Phase Inverters for Unbalanced Loads in Hybrid Power Systems

Abstract

A key component at the grid side of a PV/hybrid power system (HPS) is the inverter. One of the desirable characteristics of inverters in three-phase systems is the ability to feed unbalanced loads with voltage and frequency nominal values. This paper introduces innovative three-phase inverter topologies in combination with an advanced control function able to feed isolated grids with unbalanced loads. Therefore, standardized advanced control functions based on symmetrical components will be used. In this paper a four leg power electronics topology in combination with the developed control algorithm is used to perform a three-phase symmetrical voltage source with a controlled neutral point. The advantages of the developed control function will be introduced and discussed by a simulation study