Person: UrsĂșa Rubio, Alfredo
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UrsĂșa Rubio
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Alfredo
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IngenierĂa ElĂ©ctrica, ElectrĂłnica y de ComunicaciĂłn
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ISC. Institute of Smart Cities
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0000-0001-6240-8659
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3245
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Publication Open Access Zero-loss switching in LLC resonant converters under discontinuous conduction mode: analysis and design methodology(IEEE, 2023) Elizondo MartĂnez, David; Barrios RĂpodas, Ernesto; Larequi, Ăñigo; UrsĂșa Rubio, Alfredo; Sanchis GĂșrpide, Pablo; IngenierĂa ElĂ©ctrica, ElectrĂłnica y de ComunicaciĂłn; Institute of Smart Cities - ISC; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren; Universidad PĂșblica de Navarra / Nafarroako Publikoa UnibertsitateMany thriving applications where isolation is required, such as LED drivers, traction and EV fast charging, implement LLC resonant converters, particularly when voltage regulation is not required or an additional conversion stage is in charge of it. The LLC converter can be operated under discontinuous conduction mode (DCM), due to its advantages such as unregulated and sensorless operation, fixed switching frequency and voltage gain, and zero-current switching (ZCS). However, ZCS results in EMI and switching losses in the primary converter, particularly forâ„1200-V devices. Alternatively, zero-loss switching (ZLS) can be accomplished by means of a proper design of the LLC converter, overcoming the drawbacks of ZCS. The focus of this paper is to perform an exhaustive research on the LLC converter under DCM-ZLS: discontinuous conduction mode with lossless switching in the primary and secondary sides. As a result of this analysis, a set of design boundaries are deduced for parameters such as the magnetizing inductance, the leakage inductance, and the gate resistance. A comprehensive, step-by-step design methodology is proposed and applied to a 18-kW, 200-kHz test bench. The designed parameters are implemented in the converter and several experiments are conducted, including a test at rated input voltage and rated power (600 V, 18 kW). The conduction states studied theoretically in the analysis of the LLC converter are identified in the experimental results, and the operation of the test bench under DCM-ZLS is verified.Publication Open Access Modelling of PEM fuel cell performance: steady-state and dynamic experimental validation(MDPI, 2014) San MartĂn Biurrun, Idoia; UrsĂșa Rubio, Alfredo; Sanchis GĂșrpide, Pablo; IngenierĂa ElĂ©ctrica y ElectrĂłnica; Ingeniaritza Elektrikoa eta Elektronikoa; Gobierno de Navarra / Nafarroako GobernuaThis paper reports on the modelling of a commercial 1.2 kW proton exchange membrane fuel cell (PEMFC), based on interrelated electrical and thermal models. The electrical model proposed is based on the integration of the thermodynamic and electrochemical phenomena taking place in the FC whilst the thermal model is established from the FC thermal energy balance. The combination of both models makes it possible to predict the FC voltage, based on the current demanded and the ambient temperature. Furthermore, an experimental characterization is conducted and the parameters for the models associated with the FC electrical and thermal performance are obtained. The models are implemented in Matlab Simulink and validated in a number of operating environments, for steady-state and dynamic modes alike. In turn, the FC models are validated in an actual microgrid operating environment, through the series connection of 4 PEMFC. The simulations of the models precisely and accurately reproduce the FC electrical and thermal performance.Publication Open Access On the requirements of the power converter for second-life lithium-ion batteries(IEEE, 2019) Berrueta Irigoyen, Alberto; San MartĂn Biurrun, Idoia; Pascual Miqueleiz, Julio MarĂa; Sanchis GĂșrpide, Pablo; UrsĂșa Rubio, Alfredo; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren; Institute of Smart Cities - ISC; IngenierĂa ElĂ©ctrica, ElectrĂłnica y de ComunicaciĂłn; Gobierno de Navarra / Nafarroako GobernuaThe use of lithium-ion batteries is increasing year after year, especially in the automotive sector. Given the high requirements of electric vehicles, their energy storage systems are discarded when they still have around 70% of its initial capacity. These discarded batteries are being studied as a low-price option for stationary systems, mostly related to renewable energy generation, with lower battery requirements. However, the increasing dispersion of cell capacity detailed in this contribution limits the use of second-life cells if regular battery management systems and power converters. We present in this contribution an experimental comparison of the capacity dispersion between fresh and second-life cells, and detail the relationship between the capacity dispersion and the required BMS functionality. Furthermore, we include the ageing phenomena in the analysis by means of experimental ageing results, given that the capacity dispersion is enlarged as the battery ages. After this, we use this data to quantify advantages and disadvantages of a combined BMS and power converter, based on a multilevel topology, compared to a conventional BMS. The most relevant result, when a 55-cell battery is analysed, is a 65% increase in capacity during its whole second life if the BMS and power converter are combined by means of a multilevel topology. The increased level of complexity required by the combined BMS-power converter architecture is analysed in this contribution, providing a convenient tool for the selection of the most suitable option for each application.Publication Open Access Integration of second-life batteries in residential microgrids and fast charging stations(IEEE, 2022) San MartĂn Biurrun, Idoia; Braco Sola, Elisa; MartĂn Castilla, Ălvaro; Sanchis GĂșrpide, Pablo; UrsĂșa Rubio, Alfredo; IngenierĂa ElĂ©ctrica, ElectrĂłnica y de ComunicaciĂłn; Institute of Smart Cities - ISC; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren; Gobierno de Navarra / Nafarroako GobernuaThe potential of batteries from electric vehicles to be given a second life in stationary applications could be starting to become a reality in few years. However, the technical and economic feasibility of such second-life batteries (SLBs) is still uncertain. In this context, this paper analyses the real operation of a SLB in three scenarios: two of residential microgrids with photovoltaic generation under different strategies, and a fast charging station for electric mobility. To this end, three energy management strategies are developed, the first of which seeks to maximise the self-consumption of a typical household with photovoltaic generation; the second, in addition to maximising self-consumption, presents a night-time charge and peak shaving of the contract power from the grid; and the last refers to an urban bus charging station in which the aim is to reduce the contract power from the grid. Experimental validation of SLB during more than three weeks of operation in each of the scenarios have proved the technical viability of these batteries in the applications analysed.Publication Open Access Hydrogen-based energy storage for a distributed generation system(Spanish Hydrogen Association, 2016) San MartĂn Biurrun, Idoia; Berrueta Irigoyen, Alberto; UrsĂșa Rubio, Alfredo; Sanchis GĂșrpide, Pablo; IngenierĂa ElĂ©ctrica, ElectrĂłnica y de ComunicaciĂłn; Ingeniaritza Elektrikoa, Elektronikoa eta Telekomunikazio Ingeniaritza; Institute of Smart Cities - ISCOne of the most typical distributed generation systems are electrical microgrid, which consist on small electrical grids, generally connected to the main grid, with a decentralized management structure. Electrical microgrids allow higher renewable energy integration in the grid, achieving a cost decrease and improving the grid quality [1]. These mi- crogrids incorporate renewable generation systems and energy consumers. Moreover, they have storage systems to balance generation and consumption as well as the exchanged power with the main grid. Traditionally, lead-acid batter- ies have been used in microgrids. However, these batteries have some drawbacks, being the most important its poor performance in partial state of charge, which is critical for a microgrid. A suitable option for the storage system is hy- drogen technology. These systems have high energy density, which makes the storage system able to assume seasonal variability of renewable resources. This paper proposes a sizing methodology for storage systems based on hydrogen for grid-tied electrical microgrids. This methodology optimizes the relationship between the storage system size and the consumption of grid power.Publication Open Access Smart charging station with photovoltaic and energy storage for supplying electric buses(IEEE, 2022) Berrueta Irigoyen, Alberto; Astrain Escola, JosĂ© Javier; Puy PĂ©rez de Laborda, Guillermo; El Hamzaoui, Ismail; UrsĂșa Rubio, Alfredo; Sanchis GĂșrpide, Pablo; Villadangos Alonso, JesĂșs; Falcone Lanas, Francisco; LĂłpez MartĂn, Antonio; MatĂas Maestro, Ignacio; Institute of Smart Cities - ISCA Smart Charging Station (SCS) has been installed in the Public University of Navarre, Spain, in the framework of the H2020 Smart City Lighthouse STARDUST project. The SCS consists of a high-power electric bus charging point (300 kW), a 100 kW photovoltaic system, a 84 kWh support energy storage system based on a second-life lithiumion battery, and a monitoring and control system that allows the safe storage and convenient access to operation data. This SCS operates as a Smart Grid, being able to provide the power peaks required by the electric bus charger, reducing and smoothing the power demanded from the distribution grid and increasing the renewable energy self-consumption rate. This contribution presents a novel monitoring and control system, which is a key tool to integrate this SCS in the data infrastructure of a Smart City, as well as an energy management system able to operate the SCS to achieve the above-mentioned technical requirements. The crucial role of the monitoring and control system and the energy management system becomes evident in this work.Publication Open Access Impact of micro-cycles on the lifetime of lithium-ion batteries - EIS analysis(IEEE, 2024-07-30) NovĂĄkovĂĄ, Katerina; Berrueta Irigoyen, Alberto; Soto Cabria, AdriĂĄn; Sanchis GĂșrpide, Pablo; UrsĂșa Rubio, Alfredo; IngenierĂa ElĂ©ctrica, ElectrĂłnica y de ComunicaciĂłn; Ingeniaritza Elektrikoa, Elektronikoa eta Telekomunikazio Ingeniaritza; Institute of Smart Cities - ISC; Gobierno de Navarra / Nafarroako GobernuaExperimental studies of lithium-ion batteries are very often based only on deep charge and discharge cycles. However, these test profiles do not fully reflect the actual operation of the battery in an electric vehicle or in stationary applications, where the battery is not only loaded during the main charging and discharging profiles, but it is also stressed by the current throughput caused by renewable power fluctuations or by auxiliary services. These cycles, which are superimposed to the main charge and discharge processes and have a depth of discharge not exceeding 2%, are called micro-cycles. Although there are several simulation studies that attempt to capture this issue, there is still no comprehensive experimental study that has the phenomena that occur during micro-cycling. This paper presents an experimental analysis of micro-cycles, providing a detailed view of the different processes taking place in the battery during aging, by means of a detailed analysis of the results from electrochemical impedance spectroscopy (EIS). By studying the single electrochemical processes in detail, this paper explains the benefits of micro-cycling in terms of extending the lifetime of the battery.Publication Open Access Critical comparison of energy management algorithms for lithium-ion batteries in renewable power plants(IEEE, 2019) Berrueta Irigoyen, Alberto; Soto Cabria, AdriĂĄn; GarcĂa Solano, Miguel; Parra Laita, Ăñigo de la; Sanchis GĂșrpide, Pablo; UrsĂșa Rubio, Alfredo; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren; Institute of Smart Cities - ISC; IngenierĂa ElĂ©ctrica, ElectrĂłnica y de ComunicaciĂłn; Universidad PĂșblica de Navarra / Nafarroako Unibertsitate PublikoaLithium-ion batteries are gaining importance for a variety of applications due to their price decrease and characteristics improvement. A good energy management strategy is required in order to increase the profitability of an energy system using a Li-ion battery for storage. The vast number of management algorithms that has been proposed to optimize the achieved profit, with diverse computational power requirements and using models with different complexity, raise doubts about the suitability of an algorithm and the required computation power for a particular application. The performance of three energy management algorithms based on linear, quadratic, and dynamic programming are compared in this work. A realistic scenario of a medium-sized PV plant with a constraint of peak shaving is used for this comparison. The results achieved by the three algorithms are compared and the grounds of the differences are analyzed. Among the three compared algorithms, the quadratic one seems to be the most suitable for renewableenergy applications, given the undue simplification of the battery aging required by the linear algorithm and the discretization and computational power required by a dynamic algorithm.Publication Open Access Inertial response and inertia emulation in DFIG and PMSG wind turbines: emulating inertia from a supercapacitor-based energy storage system(IEEE, 2021) SacristĂĄn Sillero, Javier; Goñi, Naiara; Berrueta Irigoyen, Alberto; LĂłpez Taberna, JesĂșs; RodrĂguez Rabadan, JosĂ© Luis; UrsĂșa Rubio, Alfredo; Sanchis GĂșrpide, Pablo; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren; Institute of Smart Cities - ISC; IngenierĂa ElĂ©ctrica, ElectrĂłnica y de ComunicaciĂłn; Universidad PĂșblica de Navarra / Nafarroako Unibertsitate PublikoaThe increasing wind power penetration in electrical power systems results in a reduction of operative conventional power plants. These plants include synchronous generators directly connected to the grid. Facing a change in grid frequency, these generators inherently respond by varying their stored kinetic energy and their output power, which contributes to grid stability. Such a response is known as inertial response. Wind turbines (WTs) are mostly based on Doubly-Fed Induction Generator (DFIG) or Permanent Magnet Synchronous Generator (PMSG) machines. Their power electronics interface decouples the electromechanical behaviour of the generator from the power grid, making their inertial response null or insignificant. Therefore, in order not to weaken the frequency response of the power system, WTs must be able to react to frequency variations by changing their output power, i.e., emulating an inertial response. Common techniques for inertia emulation in WTs rely on pitch control and stored kinetic energy variation. This contribution proposes a strategy (applicable for both DFIG and PMSG) which uses the energy stored in a supercapacitor connected to the back-to-back converter DC link to emulate the inertial response. Its performance is compared by simulation with aforementioned common techniques, showing ability to remove certain limitations.Publication Open Access Boost DC-AC inverter: a new control strategy(IEEE, 2005) Sanchis GĂșrpide, Pablo; UrsĂșa Rubio, Alfredo; GubĂa Villabona, Eugenio; Marroyo Palomo, Luis; IngenierĂa ElĂ©ctrica, ElectrĂłnica y de ComunicaciĂłn; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio IngeniaritzarenBoost dcâac inverter naturally generates in a single stage an ac voltage whose peak value can be lower or greater than the dc input voltage. The main drawback of this structure deals with its control. Boost inverter consists of Boost dcâdc converters that have to be controlled in a variable-operation point condition. The sliding mode control has been proposed as an option. However, it does not directly control the inductance averaged-current. This paper proposes a control strategy for the Boost inverter in which each Boost is controlled by means of a double-loop regulation scheme that consists of a new inductor current control inner loop and an also new output voltage control outer loop. These loops include compensations in order to cope with the Boost variable operation point condition and to achieve a high robustness to both input voltage and output current disturbances. As shown by simulation and prototype experimental results, the proposed control strategy achieves a very high reliable performance, even in difficult transient situations such as nonlinear loads, abrupt load changes, short circuits, etc., which sliding mode control cannot cope with.