Accurate Power Sharing With Harmonic Power for Islanded Multibus Microgrids

In an islanded multibus microgrid, accurate power sharing is more difficult than in a traditional single-bus microgrid due to its complex inner structure. This paper proposes an enhanced power sharing control scheme to share accurately dominant harmonic powers for the multibus microgrids with the aid of adaptive regulation of the virtual impedances at dominant frequencies. The proposed control method provides accurate harmonic power sharing even when the microgrid configuration or the load condition is changed. Moreover, a simple secondary controller has also been proposed to remove the frequency/voltage deviations without additional voltage measurement at the point of common coupling. The proposed control scheme can be implemented directly in any type of the microgrid structure (single bus or multibus) without any information about the detailed microgrid configuration, feeder impedances, and the load powers, which decreases complexity and system cost. The proposed control method is theoretically investigated, and its feasibility and effectiveness are validated via simulation and experiment.