7 research outputs found

    Modelling and control for bounded synchronization in multi-terminal VSC-HVDC transmission networks

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    © 20xx IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.The extension and size of the power grid is expected to increase in the near future. Managing such a system presents challenging control problems that, so far, have been approached with classical control techniques. However, large scale systems of interconnected nodes fall within the framework of the emerging field of complex networks. This paper models multi-terminal VSC-HVDC systems as a complex dynamical network, and derives conditions ensuring bounded synchronization of its trajectories for a family of controllers. The obtained results are validated via numerical simulations.Postprint (author's final draft

    Adaptive Control of Dynamically Complex Networks with Saturation Couplings

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    This paper considers the control problem of dynamically complex networks with saturation couplings. Two novel control schemes in terms of adaptive control are presented to deal with such saturation couplings. Based on the robust idea, the underlying complex network is firstly transformed into a strongly connected network having time-varying uncertainty. However, the upper bound of uncertainty is unknown. Because of such an unavailable bound, a kind of adaptive controller added to each node is proposed such that the closed-loop auxiliary network is uniformly bounded. In particular, the original system states are asymptotically stable. Moreover, in order to avoid adding the desired controller to every node, another different kind of adaptive controller based on the pinning control idea is proposed. Compared with the former method, it is only applied to a part of nodes and has a good operability. Finally, a numerical example is provided to show the effectiveness of our results

    Resilient Learning-Based Control for Synchronization of Passive Multi-Agent Systems under Attack

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    In this paper, we show synchronization for a group of output passive agents that communicate with each other according to an underlying communication graph to achieve a common goal. We propose a distributed event-triggered control framework that will guarantee synchronization and considerably decrease the required communication load on the band-limited network. We define a general Byzantine attack on the event-triggered multi-agent network system and characterize its negative effects on synchronization. The Byzantine agents are capable of intelligently falsifying their data and manipulating the underlying communication graph by altering their respective control feedback weights. We introduce a decentralized detection framework and analyze its steady-state and transient performances. We propose a way of identifying individual Byzantine neighbors and a learning-based method of estimating the attack parameters. Lastly, we propose learning-based control approaches to mitigate the negative effects of the adversarial attack

    Output Synchronization of Dynamical Networks with Incrementally-dissipative Nodes and Switching Topology

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    This paper studies asymptotic output synchronization for a class of dynamical networks with identical nonlinear nodes and switching topology. The node dynamics are characterized by a quadratic form of incremental-dissipativity. The output synchronization problem of the switched network is first converted into the set stability problem for the interconnected nonlinear system with a particular selection of input-output pair, which preserves dissipativity. Then, synchronization under arbitrary switching among self-synchronizing subnetworks and synchronization by design of switching among subnetworks, where none of them is necessarily self-synchronizing, are investigated by using the common Lyapunov function method and the single Lyapunov function method, respectively. Algebraic synchronization criteria for both cases are established, and the obtained results are applied to the investigation of coupled biochemical oscillators and coupled Chua's circuits

    Output synchronization of dynamical networks with incrementally-dissipative nodes and switching topology

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    We study the fronts that appear when a shear-thickening suspension is submitted to a sudden driving force at a boundary. Using a quasi-one-dimensional experimental geometry, we extract the front shape and the propagation speed from the suspension flow field and map out their dependence on applied shear. We find that the relation between stress and velocity is quadratic, as is generally true for inertial effects in liquids, but with a pre-factor that can be much larger than the material density. We show that these experimental findings can be explained by an extension of the Wyart-Cates model, which was originally developed to describe steady-state shear-thickening. This is achieved by introducing a sole additional parameter: the characteristic strain scale that controls the crossover from start-up response to steady-state behavior. The theoretical framework we obtain unifies both transient and steady-state properties of shear-thickening materials.Comment: 17 pages, 13 figure
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