Prescribed-time extended state observer-based resilient secondary control for AC microgrids under denial-of-service...

This paper proposes a resilient secondary control strategy for islanded AC microgrids under denial-of-service (DoS) attacks to achieve voltage recovery while ensuring their transient performance. First, a prescribed-time extended state observer (PTESO) is designed to estimate system states and nonlinear uncertainties that are difficult to measure directly. Second, a resilient PID-like sliding mode control (SMC) strategy with two modes is developed. In safe mode, a PID-like SMC scheme based on an event-triggered mechanism (ETM) is employed, incorporating a designed error compensation term. In attack-response mode, once a DoS attack is detected, the last received PTESO-based neighbor estimates are retained, and a PID-like SMC scheme based on the ETM is reconfigured to restore voltage rapidly. Third, a piecewise Lyapunov function is constructed to prove that the proposed resilient controller ensures all signals of the system are bounded. In addition, the Zeno phenomenon is avoided. Finally, the effectiveness of the proposed method is demonstrated through MATLAB/Simulink simulations and hardware-in-the-loop experiments.