7 research outputs found

    Optimal power flow for resistive DC networks: a port-hamiltonian approach

    Get PDF
    This paper studies the optimal power flow problem for resistive DC networks. The gradient method algorithm is written in a port-Hamiltonian form and the stability of the resulting dynamics is studied. Stability conditions are provided for general cyclic networks and a solution, when these conditions fail, is proposed. In addition, the results are exemplified by means of numerical simulations.Postprint (published version

    A Robust Consensus Algorithm for Current Sharing and Voltage Regulation in DC Microgrids

    Get PDF
    In this paper a novel distributed control algorithm for current sharing and voltage regulation in Direct Current (DC) microgrids is proposed. The DC microgrid is composed of several Distributed Generation units (DGUs), including Buck converters and current loads. The considered model permits an arbitrary network topology and is affected by unknown load demand and modelling uncertainties. The proposed control strategy exploits a communication network to achieve proportional current sharing using a consensus-like algorithm. Voltage regulation is achieved by constraining the system to a suitable manifold. Two robust control strategies of Sliding Mode (SM) type are developed to reach the desired manifold in a finite time. The proposed control scheme is formally analyzed, proving the achievement of proportional current sharing, while guaranteeing that the weighted average voltage of the microgrid is identical to the weighted average of the voltage references.Comment: 12 page

    Design and simulation of a supervisor algoritghm for a HVDC network

    Get PDF
    Aquest projecte té com a objectiu la creació d’un algoritme que optimitzi els resultats d’una simulació del control d’una xarxa MTDC i convertir aquesta recreació en un procés automàtic. Una vegada aquest algoritme hagi estat implementat en el model de control i els resultats obtinguts s’hagin validat confirmant el correcte funcionament del mateix, el següent pas serà dur a terme varies simulacions per diferents topologies de xarxes i comparà els resultats obtinguts pels diferents casos, analitzant la resposta i el comportament de la xarxa davant de les diferents situacions d’explotació i els canvis desitjats

    Simulation and optimization of an HVDC network connecting offshore windfarms with the mainland

    Get PDF
    In this project an algorithm capable of simulating a network connecting offshore wind farms HVDC points with consumers has been created. This simulation takes into account the analytical model that HVDC network is based on. The simulation also takes into account the control that is applied in such cases. In addition, the control of the system calculates the optimum working point to optimise the network energy transfer

    Commande non-linéaire et analyse de stabilité de réseaux multi-terminaux haute tension à courant continu

    Get PDF
    This dissertation was devoted to the study of multi-terminal high voltage direct current (MTDC) networks. The main contributions were in the field of nonlinear automatic control, applied to power systems, power electronics and renewable energy sources. The research work was started with the intention of filling some gaps between the theory and the practice, in particular: 1) to investigate various control approaches for the purpose of improving the performance of MTDC systems; 2) to establish connections between existing empirical control design and theoretical analysis; 3) to improve the understanding of the multi-time-scale behavior of MTDC systems characterized by the presence of slow and fast transients in response to external disturbances. As a consequence, this thesis work can be put into three areas, namely nonlinear control design of MTDC systems, analysis of MTDC system's dynamic behaviors and application of MTDC systems for frequency control of AC systems.Cette thèse a été consacrée à l'étude des réseaux multi-terminaux haute tension à courant continu (MTDC). Les principales contributions étaient dans le domaine du contrôle automatique non linéaire, appliquées aux systèmes électriques, électronique de puissance et les sources d'énergie renouvelables. Le travail de recherche a été lancé avec l'intention de combler certaines lacunes entre la théorie et la pratique, en particulier: 1) d'enquêter sur diverses approches de contrôle pour le but d'améliorer la performance des systèmes MTDC; 2) d'établir des connexions entre la conception du contrôle empiriques existantes et analyse théorique; 3) d'améliorer la compréhension du comportement multi-échelle de temps des systèmes MTDC caractérisés par la présence de transitoires lents et rapides en réponse aux perturbations externes. En conséquence, ce travail de thèse peut être mis en trois domaines, à savoir la conception non linéaire de commande de systèmes MTDC, analyse des comportements dynamiques de système MTDC et l'application de systèmes MTDC pour le contrôle de fréquence des systèmes de climatisation

    Strictly convex loss functions for port-Hamiltonian based optimization algorithm for MTDC networks

    No full text
    In this work we propose a primal-dual method that can be cast in a port-Hamiltonian framework for minimizing the power losses in a multi-terminal DC network. The main contribution consists of proposing an alternative power loss function by means of a change of variables that translates the convex objective function into a strictly convex objective function. The results hold under some restrictive assumptions, but necessary to make steps towards a complete algorithm in future research. The obtained results are validated via numerical simulations
    corecore