Distributed Event-Triggered Control for Islanded Microgrids: Cyber-Physical Design and Implementation

Microgrid is a complex cyber-physical system with interacted power and communication networks. Conventionally, the secondary control of microgrids relies on a central controller and periodic communications, which may limit the efficiency and resilience of the cyber systems. In this paper, a distributed event-triggered secondary control scheme is proposed for efficient communication in islanded microgrids. The proposed control scheme only takes effect when there are microgrid states change `events' (e.g load changes and communication failures). The secondary control including frequency/voltage regulation and accurate real/reactive power sharing are decoupled into two timescales. The triggering conditions for only power sharing control in slower timescale are defined to avoid overlap. The proposed method only requires communications among neighbour controllers at the event-triggered time, which dramatically reduces the communication burden in the cyber system. A cyber-physical microgrid platform has been built with the microgrids in OPAL-RT and communications in Raspberry Pis. The proposed secondary controller has been implemented on this platform and the hardware-in-the-loop (HiL) experiment results demonstrate the performance of our controller design.