Abstract
The exchange of information among distributed energy resources (DERs) in microgrids (MGs) relies on sensing and communication systems, which makes them vulnerable to cybersecurity threats. This article proposes an enhanced secondary control strategy based on an asynchronous self-triggered secure mechanism (ASTSM) for ac autonomous MGs operating under switching communication topologies and subject to distributed denial-of-service (DDoS) attacks. The proposed distributed edge-based resilient approach improves communication efficiency, reduces computational demands, and eliminates the continuous monitoring burden inherent in event-triggered schemes. Moreover, ASTSM is specifically designed to counter DDoS attacks launched by multiple adversaries while ensuring the exclusion of Zeno behavior. In the proposed framework, each communication edge between DERs is equipped with a local time-sequence update algorithm that pre-calculates the next triggering instant based on the most recent states, independent of other edges. This feature strengthens the resilience of the mechanism against DDoS attacks. The effectiveness of the proposed control strategy in regulating voltage and frequency, achieving proportional active power sharing, and maintaining state-of-charge (SoC) balancing is validated through simulations in MATLAB/Simulink under various operating scenarios.