A Coordinated Control of Hybrid Single-Phase AC/DC Microgrids Based on Natural Harmonic Injection Concept

Abstract:
A hybrid single-phase AC/DC microgrid forms by connecting a single-phase AC microgrid to a DC one. In these systems, the DC microgrid experiences a natural injection of second harmonic current caused by the double-frequency component of the AC side instantaneous power. Based on the injected harmonic, a decentralized coordinated control is proposed to enable accurate power sharing among DC distributed energy resources (DERs) and among DC and AC DERs without imposing DC side voltage deviations. In this method, each DC DER adjusts its power based on the harmonic component frequency. Concurrently, the interlinking converter, which interconnects AC and DC microgrids, ensures the voltage level of the DC microgrid remains at the rated value.