Zero-Sum Game-Based Distributed Secondary Control for DC Microgrids Against Stealthy Attacks

This article investigates the voltage restoration problem of direct current (DC) microgrids (MGs) under stealth attacks. The fact is that secondary control requires information exchange through sparse communication networks, which makes cybersecurity the key to achieving voltage restoration. Compared with the attack signals launched by nonintelligent attackers, stealthy attack signals are more difficult to capture. Similarly, since MGs actually operate in a closed environment, malicious attackers have limited knowledge of the MG's structural information. Therefore, we reformulate the problem to a two-person zero-sum game between the attacker and defender and then seek the optimal voltage restoration control strategy. In the process of solving the optimal problem, both robustness and convergence of parameter estimation are considered in this article to enhance the feasibility of adaptive dynamic programming schemes. Additionally, while ensuring the voltage restoration performance of DC MGs and considering the constraints of actual network communication, a novel dynamic event-triggered mechanism is designed to reduce information transmission pressure. The effectiveness of the established control scheme is verified through real-time testing equipment built on OPAL-RT and comparison results.