Consensus-based distributed control scheme for PCC voltage harmonic mitigation and enhanced power sharing in islanded microgrids

Abstract

In the islanded microgrid, it is necessary to distribute the harmonic powers correctly among generators and mitigate the voltage harmonics at the point of common coupling (PCC) for effective microgrid operation. These control objectives are hard to satisfy at the same time with only one virtual impedance component. To simultaneously improve the microgrid voltage quality and share the distortion powers, a consensus-based distributed power-sharing scheme is proposed along with PCC harmonics mitigation. In the proposed control scheme, the controllable parts of output impedance at the fundamental and harmonic frequencies are separately tuned by simple integral controllers without depending on feeder impedance parameters. Compared to conventional control schemes, the proposed method is less complicated while ensuring a high voltage quality despite sudden changes in load power. A small-signal state-space model of the microgrid is analysed to validate the stability of the proposed control scheme, and its effectiveness is verified by experiments with a scaled-down microgrid system.