Decentralized Control of Unbalanced Hybrid AC/DC Microgrids for Maximum Loadability

An interlinking converter (IC) is an AC/DC converter that is used to link AC microgrids to DC microgrids, forming hybrid AC/DC microgrids. Several techniques have been demonstrated in the literature to utilize the IC for maximizing the loadability of the AC side. However, all these methods are centralized, which requires communication and extra hardware. The proposed work in this paper develops a communication-free, decentralized method to increase the loadability of hybrid AC/DC microgrids. The three-phase voltages and currents are decomposed into positive and negative sequence components. By controlling these sequences, the ICs can relieve the unbalanced power from the distributed generators on the AC side, which helps maximize their loadability. Furthermore, a decentralized coordination method is developed to share the load of the unbalanced power evenly between multiple ICs.