Distributed event-triggered fault-tolerant secondary control for DC microgrids under mixed faults and communication impairments

Abstract

This paper proposes a distributed event-triggered fault-tolerant secondary control framework for DC microgrids operating under actuator loss-of-effectiveness faults, current-sharing sensor anomalies, and communication impairments. The proposed approach integrates distributed secondary regulation, packetized event-triggered communication, residual-based fault detection and isolation, and health-aware supervisory reconfiguration within a unified control architecture. The secondary correction signals are injected into the primary layer through the exact outer-loop voltage reference update, while the supervisory mechanism modifies both the control path and the effective communication graph according to the diagnosed fault type and severity. Nominal quadratic stability is established around the healthy operating point, whereas the delayed fault-affected implementation is interpreted within a practical stability/uniform ultimate boundedness framework. Simulation results on a four-converter mesh DC microgrid demonstrate that the proposed method correctly isolates all injected fault cases and reduces the post-fault current-sharing spread by up to $$94.81\%$$ relative to the baseline event-triggered controller, while preserving DC-bus voltage regulation under single-fault, mixed-fault, and dual-actuator stress scenarios. These improvements are statistically validated through a Monte Carlo study over independent stochastic communication realizations, and a complementary robustness study shows that fault isolation remains fully reliable under FDD-model parameter mismatch of up to $$20\%$$ combined with realistic measurement noise.