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This article focuses on the development of a resilient cooperative control system for leader–follower consensus problems prone to external cyber-attacks. The attackers are assumed to adversely impact data integrity and privacy by: 1) injecting unknown bounded exogenous signals to actuators and 2) eavesdropping on the physical states of followers. To mitigate the adverse effects of such attacks on the consensus, privacy, and stability of leader–follower systems, we develop a resilient cooperative control system by introducing virtual states interconnected with the physical states in such a way that the leader–follower consensus is guaranteed under unknown false data injection cyber-attacks. The dynamics of the virtual states act as a dynamical output mask, which maps the physical states of followers to some virtual states that are exchanged via a communication network. A Lyapunov-based design framework is proposed to guarantee stability and the leader–follower consensus against cyber-attacks. The decentralized design of the control variables in the proposed resilient cooperative control approach facilitates creating a plug-and-play environment, where follower nodes can easily be plugged in/out. The effectiveness of the theoretical results is evaluated using several numerical examples and implementation on a planar robot experimental testbed.

In this article, we investigate the impact of potential state-dependent false data injection cyber-attacks on frequency synchronization and active power management in islanded ac microgrids. One potential way of affecting microgrid reliability is by forcing a generation outage. Thus, the attacker could potentially aim to desynchronize inverter-based resources in microgrids by manipulating their frequency with malicious injections. The attack signals are injected to manipulate control input channels, sensor nodes, reference values, and the information exchanged through communication networks. In order to mitigate the adverse impacts of such cyber-attacks, first, the conventional distributed consensus-based secondary control approach is modified and complemented in the presence of cyber-attacks. Second, a resilient cooperative distributed secondary control scheme is proposed by utilizing the concept of a virtual layer interconnected with the main network layer. Third, theoretical stability, resilience analysis, and design considerations of interconnection matrices are also provided. Finally, simulations through MATLAB/Simulink and experimental results are presented in order to illustrate the robust performance of the proposed control scheme.

Much like any other cyber-physical systems, direct current (dc) microgrids are at risk of cyberattacks that aim to disrupt their normal operation. To enhance the security and resilience of dc microgrids against cyberattacks, the development of resilient control strategies is crucial. This article develops a distributed control approach for dc microgrids with an emphasis on resilience against a strategic cyberattack, where an attacker selects a subset of computational nodes in microgrids’ control systems to inject bounded false attack signals and change their update rules. By means of the proposed resilient distributed control mechanism interconnected with dc microgrids, the adverse effects of the false data injection (FDI) cyberattack on average voltage regulation and proportional current sharing are mitigated. Furthermore, the stability of dc microgrids in the presence of such attacks is guaranteed via a Lyapunov-based framework. Using the proposed distributed control approach, attack detection mechanisms are developed. Furthermore, it is shown that the proposed distributed controller is able to mitigate the adverse impacts of stealthy strategic FDI attacks that can bypass the attack detection system. The effectiveness of the proposed attack-resilient distributed control approach is evaluated by simulation case studies.

This article incorporates a novel ultralocal model (ULM) control based on single input interval type-2 (SIT2) fuzzy logic control (FLC) to ensure the stable operation of a nine-level packed E-cell (PEC9) inverter in a grid-connected mode. By adopting seven switching components and a single dc source, the number of circuit components has been reduced in the PEC9 topology. This inverter has the possibility to switch various multilevel voltages (nine-, seven-, or five-level) under faulty switching devices without the need for any modification in the inverter configuration. This article proposes a ULM for the regulation of PEC9; it utilizes the input/output data of the system without adopting any parameters of the inverter where it is devoid of issues brought on by model mismatch. In the proposed structure, an extended observer error (ESO) is utilized to estimate the unmodeled dynamics of the inverter and to eliminate their effects in the feedback. Since the observer can remove the uncertainties from an unknown system, the ULM controller does not need to accurate setting of the control coefficients, which makes it a good option to be easy implementation for practical applications. In addition, an SIT2-FLC can be adopted as the supplementary controller to improve the inverter's stability by eliminating the estimation error of ESO. The time-domain experimental examinations have been carried out by conducting practical scenarios on a laboratory prototype of PEC9 to appraise the superior feasibility of the proposed scheme.