Consensus Management Designed for Independent Harmonic Compensation in AC Microgrids

Harmonic currents in microgrids (MGs) have increased significantly due to the evolving characteristics of power electronics, generation systems, and load profiles. Improper sharing of these currents among distributed generators (DGs) can lead to overload and reduced reliability. This paper proposes a consensus-based secondary control strategy that enables proportional sharing of both fundamental and harmonic currents among DGs in AC MGs. The primary control level employs voltage and current parallel control using proportional-resonant (PR) controllers. Through the exchange of current amplitudes and total harmonic distortion (THD) over a communication network, the proposed method dynamically adjusts each DG reference currents to reflect its capacity, thus preventing overload. The strategy operates seamlessly in both islanded and grid-connected modes, without switching logic states, avoiding discontinuities that could cause high-frequency oscillations or instability. Additionally, a THD equalization layer improves harmonic distribution, ensuring compliance with standard limits. Simulation and experimental results demonstrate the method's resilience to communication failures and its plug-and-play capability, highlighting its practical applicability in modern MGs.