Grupo de Sistemas Electrónicos Industriales

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Author: González Medina, Raúl × Subject: TECNOLOGIA ELECTRONICA ×

Publication Search Results

Now showing 1 - 10 of 28
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    A Control Stage for Parallel-Connected Interlinking Converters in Hybrid AC-DC Microgrids
    (Institute of Electrical and Electronics Engineers, 2023) Liberos Mascarell, María Antonia; González Medina, Raúl; Patrao Herrero, Iván; Torán Mort, Enric; Garcerá Sanfeliú, Gabriel; Figueres Amorós, Emilio; Dpto. de Ingeniería Electrónica; Escuela Técnica Superior de Ingeniería del Diseño; Escuela Técnica Superior de Ingeniería Industrial; Grupo de Sistemas Electrónicos Industriales; AGENCIA ESTATAL DE INVESTIGACION
    [EN] Having two or more interlinking converters connected in parallel in hybrid microgrids has some benefits, like modularity, flexibility, and redundancy. However, the parallelization of the inverters leads to circulating currents that can cause system malfunctions. This work uses a method for suppressing low-frequency circulating currents in interlinking converters by controlling the zero-sequence component of the phase currents, showing that the control structure is valid for interlinking converters. The proposed control scheme has been applied to two parallel interlinking inverters of 5 kW and 2.5 kW, respectively. The interlinking inverters are connected to the grid, and they control the voltage in the DC bus of the hybrid microgrid. To validate the concept, simulation and experimental results are shown.
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    DC-Bus Signaling control laws for the operation of DC-microgrids with renewable power sources
    (IEEE, 2023) Patrao Herrero, Iván; Torán Mort, Enric; González Medina, Raúl; Liberos Mascarell, María Antonia; Figueres Amorós, Emilio; Garcerá Sanfeliú, Gabriel; Dpto. de Ingeniería Electrónica; Escuela Técnica Superior de Ingeniería del Diseño; Escuela Técnica Superior de Ingeniería Industrial; Grupo de Sistemas Electrónicos Industriales; Agencia Estatal de Investigación; European Regional Development Fund; Ministerio de Asuntos Económicos y Transformación Digital
    [EN] DC-Bus Signaling (DBS) is a proven method to coordinate different microgrid agents, using the DC voltage of the microgrid as a communication signal. The droop control applied in a DC microgrid achieves accurate power-sharing among converters while leading to a certain voltage regulation error in the microgrid bus. The behaviour of the different agents in a microgrid is managed by using the voltage at each node of the microgrid as the DBS signal. The technique proposed in this paper uses an improved DBS technique to coordinate interlinking converters, photovoltaic generators, Energy Storage Systems and loads in a microgrid. The operation of the renewable power sources of a microgrid at the full generated power is desired due to economic and environmental reasons. The DBS technique proposed in this paper is adapted to integrate renewable power sources in the microgrid. The DBS-controlled Energy Storage Systems (ESS) will store the surplus energy if the generated power exceeds consumption. In the case of fully charged ESS, the renewable generators will limit their output power to those demanded by the loads. The proposed control laws have been tested in an experimental microgrid.
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    A Control Scheme to Suppress Circulating Currents in Parallel-Connected Three-Phase Inverters
    (MDPI AG, 2022-11) Liberos Mascarell, María Antonia; González Medina, Raúl; Patrao Herrero, Iván; Garcerá Sanfeliú, Gabriel; Figueres Amorós, Emilio; Dpto. de Ingeniería Electrónica; Escuela Técnica Superior de Ingeniería del Diseño; Escuela Técnica Superior de Ingeniería Industrial; Grupo de Sistemas Electrónicos Industriales; AGENCIA ESTATAL DE INVESTIGACION; European Regional Development Fund
    [EN] The parallel operation of inverters has many benefits, such as modularity and redundancy. However, the parallel connection of inverters produces circulating currents that may result in malfunctions of the system. In this work, a control technique for the elimination of the low-frequency components of the circulating currents in grid-connected inverters is presented. The proposed control structure contains n - 1 zero-sequence control loops, with n being the number of inverters connected in parallel. Simulation and experimental results have been carried out on a prototype composed of two 5 kW inverters connected in parallel. The results have been obtained by considering the following mismatches between both inverters: inductance values of the grid filters, unbalance of the delivered power, and the use of different modulation techniques.
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    Experimental Study of a Centralized Control Strategy of a DC Microgrid Working in Grid Connected Mode
    (MDPI AG, 2017) Salas-Puente, Robert Antonio; Marzal-Romeu, Silvia; González Medina, Raúl; Figueres Amorós, Emilio; Garcerá Sanfeliú, Gabriel; Dpto. de Ingeniería Electrónica; Escuela Técnica Superior de Ingeniería del Diseño; Escuela Técnica Superior de Ingeniería Industrial; Grupo de Sistemas Electrónicos Industriales; Ministerio de Economía, Industria y Competitividad
    [EN] The results concerning the integration of a set of power management strategies and serial communications for the efficient coordination of the power converters composing an experimental DC microgrid is presented. The DC microgrid operates in grid connected mode by means of an interlinking converter. The overall control is carried out by means of a centralized microgrid controller implemented on a Texas Instruments TMS320F28335 DSP. The main objectives of the applied control strategies are to ensure the extract/inject power limits established by the grid operator as well as the renewable generation limits if it is required; to devise a realistic charging procedure of the energy storage batteries as a function of the microgrid status; to manage sudden changes of the available power from the photovoltaic energy sources, of the load power demand and of the power references established by the central controller; and to implement a load shedding functionality. The experimental results demonstrate that the proposed power management methodology allows the control of the power dispatch inside the DC microgrid properly.
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    Efficient Event Notification Middleware for Smart Microgrids over P2P Networks
    (Institute of Electrical and Electronics Engineers, 2018) Marzal-Romeu, Silvia; Salas-Puente, Robert Antonio; González Medina, Raúl; Garcerá Sanfeliú, Gabriel; Figueres Amorós, Emilio; Dpto. de Ingeniería Electrónica; Escuela Técnica Superior de Ingeniería del Diseño; Escuela Técnica Superior de Ingeniería Industrial; Grupo de Sistemas Electrónicos Industriales; Ministerio de Economía y Competitividad
    [EN] Microgrids are moving towards large-scale smart distributed networks which demand an efficient and reliable communication infrastructure to manage, control and monitor energy resources. With regard to this, publisher/subscriber eventbased middleware has become relevant for large-scale distributed time applications because it allows decouple time and space between senders and receivers. Particularly the content publish/subscribe systems over structured peer-to-peer (P2P) networks has emerged to enhance scalability and dynamism of notification middleware systems. However, this type of systems use multicast routing schemes that still generate much network traffic and as a consequence an overload of the communication channel is produced. This results in inefficient network utilization and rapid depletion of network resources leading to unreliable operations, degradation of system performance and even instability of the microgrid. In this paper, a new content-based publish/subscribe notification middleware over structured P2P systems is proposed, such that smart microgrid communication requirements are met. This proposed system organizes the publications and subscriptions in a one dimensional representation using the Hilbert space filling curve. Through this representation, an innovative routing and matching algorithms are developed. Experimental results demonstrate that the proposed publisher/subscribe system significantly enhance efficiency of the system, network performance and the use of computational resources.
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    Current challenges and future trends in the field of communication architectures for microgrids
    (Elsevier, 2018) Marzal-Romeu, Silvia; Salas-Puente, Robert Antonio; González Medina, Raúl; Garcerá Sanfeliú, Gabriel; Figueres Amorós, Emilio; Dpto. de Ingeniería Electrónica; Escuela Técnica Superior de Ingeniería del Diseño; Escuela Técnica Superior de Ingeniería Industrial; Grupo de Sistemas Electrónicos Industriales; Ministerio de Economía y Competitividad; European Regional Development Fund
    [EN] The concept of microgrid has emerged as a feasible answer to cope with the increasing number of distributed renewable energy sources which are being introduced into the electrical grid. The microgrid communication network should guarantee a complete and bidirectional connectivity among the microgrid resources, a high reliability and a feasible interoperability. This is in a contrast to the current electrical grid structure which is characterized by the lack of connectivity, being a centralized-unidirectional system. In this paper a review of the microgrids information and communication technologies (ICT) is shown. In addition, a guideline for the transition from the current communication systems to the future generation of microgrid communications is provided. This paper contains a systematic review of the most suitable communication network topologies, technologies and protocols for smart microgrids. It is concluded that a new generation of peer-to-peer communication systems is required towards a dynamic smart microgrid. Potential future research about communications of the next microgrid generation is also identified.
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    A Novel Locality Algorithm and Peer-to-Peer Communication Infrastructure for Optimizing Network Performance in Smart Microgrids
    (MDPI AG, 2017) Marzal-Romeu, Silvia; González Medina, Raúl; Salas-Puente, Robert Antonio; Figueres Amorós, Emilio; Garcerá Sanfeliú, Gabriel; Dpto. de Ingeniería Electrónica; Escuela Técnica Superior de Ingeniería del Diseño; Escuela Técnica Superior de Ingeniería Industrial; Grupo de Sistemas Electrónicos Industriales; Ministerio de Economía, Industria y Competitividad
    [EN] Peer-to-Peer (P2P) overlay communications networks have emerged as a new paradigm for implementing distributed services in microgrids due to their potential benefits: they are robust, scalable, fault-tolerant, and they can route messages even with a large number of nodes which are frequently entering or leaving from the network. However, current P2P systems have been mainly developed for file sharing or cycle sharing applications where the processes of searching and managing resources are not optimized. Locality algorithms have gained a lot of attention due to their potential to provide an optimized path to groups with similar interests for routing messages in order to get better network performance. This paper develops a fully functional decentralized communication architecture with a new P2P locality algorithm and a specific protocol for monitoring and control of microgrids. Experimental results show that the proposed locality algorithm reduces the number of lookup messages and the lookup delay time. Moreover, the proposed communication architecture heavily depends of the lookup used algorithm as well as the placement of the communication layers within the architecture. Experimental results will show that the proposed techniques meet the network requirements of smart microgrids even with a large number of nodes on stream.
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    Practical Analysis and Design of a Battery Management System for a Grid-Connected DC Microgrid for the Reduction of the Tariff Cost and Battery Life Maximization
    (MDPI AG, 2018) Salas-Puente, Robert Antonio; Marzal-Romeu, Silvia; González Medina, Raúl; Figueres Amorós, Emilio; Garcerá Sanfeliú, Gabriel; Dpto. de Ingeniería Electrónica; Escuela Técnica Superior de Ingeniería del Diseño; Escuela Técnica Superior de Ingeniería Industrial; Grupo de Sistemas Electrónicos Industriales; Ministerio de Economía, Industria y Competitividad
    [EN] This study is focused on two areas: the design of a Battery Energy Storage System(BESS) for a grid-connected DC Microgrid and the power management of that microgrid. The power management is performed by a Microgrid Central Controller (MGCC). A Microgrid operator provides daily information to the MGCC about the photovoltaic generation profile, the load demand profile, and the real-time prices of the electricity in order to plan the power interchange between the BESS and the main grid, establishing the desired state of charge (SOC) of the batteries at any time. The main goals of the power management strategy under study are to minimize the cost of the electricity that is imported from the grid and to maximize battery life by means of an adequate charging procedure, which sets the charging rate as a function of the MG state. Experimental and simulation results in many realistic scenarios demonstrate that the proposed methodology achieves a proper power management of the DC microgrid.
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    Measurement of the Loop Gain Frequency Response of Digitally Controlled Power Converters
    (Institute of Electrical and Electronics Engineers, 2010) González Espín, Francisco José; Figueres Amorós, Emilio; Garcerá Sanfeliú, Gabriel; González Medina, Raúl; Pascual Molto, Marcos; Dpto. de Física Aplicada; Dpto. de Ingeniería Electrónica; Escuela Técnica Superior de Ingeniería del Diseño; Escuela Técnica Superior de Ingeniería Industrial; Escuela Politécnica Superior de Alcoy; Grupo de Sistemas Electrónicos Industriales; Ministerio de Educación y Ciencia
    [EN] The study of the loop gain frequency response in a power converter is a powerful tool commonly used for the design of the controllers used in the control stage. As the control of medium- and high-power electronic converters is usually performed digitally, it is useful to find a method to measure the digital loop gains. The purpose of this paper is to present a method for properly measuring the loop gain frequency response of digitally controlled power converters by means of an analog frequency response analyzer (FRA). An analog sinusoidal reference signal generated by the FRA is injected through an analog-to-digital converter into the digital controller, and added to the discrete feedback signal. To obtain the frequency response of the open-loop gain, both feedback and disturbed feedback signals are sent back to the FRA by using the pulsewidth modulation peripherals of the controller.
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    Effects of the PWM carrier signals synchronization on the DC-link current in back-to-back converters
    (Elsevier, 2010) González Morales, Luis Gerardo; Garcerá Sanfeliú, Gabriel; Figueres Amorós, Emilio; González Medina, Raúl; Dpto. de Ingeniería Electrónica; Escuela Técnica Superior de Ingeniería del Diseño; Escuela Técnica Superior de Ingeniería Industrial; Grupo de Sistemas Electrónicos Industriales
    [EN] This paper presents a study about the synchronization effects of the PWM carrier signals of a back-to-back converter for grid connection of Wind Energy Conversion Systems based on Permanent Magnet Synchronous Generators. It is demonstrated by means of a spectral analysis that, with the proper synchronization of the carrier signals of both the rectifier and inverter stages, the rms value of the current through the DC-link capacitors is greatly reduced. As a result, the number of capacitors needed to build the back-to-back converter decreases, whereas its life cycle is expanded, so that the Wind Energy Conversion System becomes more cost effective. It is shown that the worst case occurs when the phase difference between both carrier signals is ±¿/2, yielding the highest rms value of the DC-link capacitors current. In that case the harmonic with the highest rms value is located at twice the switching frequency. The theoretical analysis is compared with experimental results from a 10 kW back-to-back converter in order to validate the effects of the carrier signals phase shift on the DC-link capacitors current.