Distributed Nonlinear Hierarchical Control of AC Microgrid via Unreliable Communication

Distributed control scheme has been widely investigated for microgrid systems in consideration of the multitude of the distributed generators. However, as the foundation of the distributed control scheme, the communication network may not always be reliable, which could deteriorate system performance, or even lead to system collapse. In order to address this problem, in this paper, a novel nonlinear hierarchical control approach is proposed, which enables the frequency and voltage regulation of an islanded ac microgrid via unreliable communication network. It is proved that the proposed control approach is robust against unreliable communication network as long as the switching graph associated with the communication network satisfies a mild condition, called jointly connected condition. Comprehensive case studies under different communication environments are conducted to validate the effectiveness of the proposed control approach.