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

Area of Science:

• Electrical Engineering
• Control Systems
• Cybersecurity

Background:

• Islanded AC microgrids are vulnerable to cyberattacks like denial-of-service (DoS).
• Maintaining stable voltage and transient performance during attacks is critical for microgrid operation.
• Existing control strategies may not adequately address the dynamic challenges posed by DoS attacks.

Purpose of the Study:

• To propose a resilient secondary control strategy for islanded AC microgrids.
• To achieve rapid voltage recovery and ensure transient performance under DoS attacks.
• To enhance the security and reliability of microgrid operations.

Main Methods:

• Design of a prescribed-time extended state observer (PTESO) for state and uncertainty estimation.
• Development of a two-mode PID-like sliding mode control (SMC) strategy with an event-triggered mechanism (ETM).
• Utilization of retained PTESO-based neighbor estimates in attack-response mode for rapid voltage restoration.
• Construction of a piecewise Lyapunov function to guarantee system boundedness and avoid the Zeno phenomenon.

Main Results:

• The proposed resilient controller effectively estimates system states and nonlinear uncertainties.
• The two-mode SMC strategy ensures voltage recovery and maintains transient performance during DoS attacks.
• Stability analysis confirms that all system signals remain bounded, and the Zeno phenomenon is avoided.
• Simulations and hardware-in-the-loop experiments validate the effectiveness of the proposed method.

Conclusions:

• The developed resilient secondary control strategy enhances the robustness of islanded AC microgrids against DoS attacks.
• The combination of PTESO and event-triggered SMC provides a reliable solution for voltage regulation under cyber threats.
• The proposed approach offers a promising direction for securing future microgrid systems.