Open Access
Multifunctional protective PVC-ZnO nanocomposite coatings deposited on aluminum alloys by electrospinning
(MDPI, 2019) Iribarren Zabalegui, Álvaro; Rivero Fuente, Pedro J.; Berlanga Labari, Carlos; Larumbe Abuin, Silvia; Miguel, Adrián; Rodríguez Trías, Rafael; Ingeniaritza; Institute for Advanced Materials and Mathematics - INAMAT2; Ingeniería; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa, PRO-UPNA 18 (6107)
This paper reports the use of the electrospinning technique for the synthesis of nanocomposite micro/nanofibers by combining a polymeric precursor with hydrophobic behavior like polyvinyl chloride (PVC) with nanoparticles of a corrosion inhibitor like ZnO. These electrospun fibers were deposited on substrates of the aluminum alloy 6061T6 until forming a coating around 100 m. The effect of varying the different electrospinning deposition parameters (mostly applied voltage and flow-rate) was exhaustively analyzed in order to optimize the coating properties. Several microscopy and analysis techniques have been employed, including optical microscopy (OM), field emission scanning electron microscopy (FE-SEM), atomic force microscopy (AFM), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). Water contact angle (WCA) measurements have been carried out in order to corroborate the coating hydrophobicity. Finally, their corrosion behavior has been evaluated by electrochemical tests (Tafel curves and pitting potential measurements), showing a relevant improvement in the resultant corrosion resistance of the coated aluminum alloys.
Open Access
Dynamic modeling of a pressurized alkaline water electrolyzer: a multiphysics approach
(IEEE, 2023) Iribarren Zabalegui, Álvaro; Elizondo Martínez, David; Barrios Rípodas, Ernesto; Ibaiondo, Harkaitz; Sánchez Ruiz, Alain; Arza, Joseba; Sanchis Gúrpide, Pablo; Ursúa Rubio, Alfredo; Ingeniería Eléctrica, Electrónica y de Comunicación; Institute of Smart Cities - ISC; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren
In this paper a dynamic model for the simulation of pressurized alkaline water electrolyzers is presented. The model has been developed following a multiphysics approach, integrating electrochemical, thermodynamic, heat transfer and gas evolution processes in order to faithfully reproduce the complete dynamical behavior of these systems. The model has been implemented on MATLAB/Simulink and validated through experimental data from a 1 Nm3/h commercial alkaline water electrolyzer. Validations have been performed under real scenarios where the electrolyzer is working with power profiles characteristic from renewable sources, wind and photovoltaic. The simulated results have been found to be consistent with the real measured values. This model has a great potential to predict the behavior of alkaline water electrolyzers coupled with renewable energy sources, making it a very useful tool for designing efficient green hydrogen production systems.
Open Access
Dynamic modeling and simulation of a pressurized alkaline water electrolyzer: a multiphysics approach
(IEEE, 2021) Iribarren Zabalegui, Álvaro; Barrios Rípodas, Ernesto; Ibaiondo, Harkaitz; Sánchez Ruiz, Alain; Arza, Joseba; Sanchis Gúrpide, Pablo; Ursúa Rubio, Alfredo; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren; Institute of Smart Cities - ISC; Ingeniería Eléctrica, Electrónica y de Comunicación
In this paper a dynamic model for the simulation of pressurized alkaline water electrolyzers is presented. The model has been developed following a multiphysics approach, integrating electrochemical, thermodynamic, heat transfer and gas evolution processes in order to faithfully reproduce the complete dynamical behavior of these systems. The model has been implemented on MATLAB/Simulink and validated through experimental data from a 1 Nm3h-1 commercial alkaline water electrolyzer, and the simulated results have been found to be consistent with the real measured values. This model has a great potential to predict the behavior of alkaline water electrolyzers coupled with renewable energy sources, making it a very useful tool for designing efficient green hydrogen production systems.
Open Access
Asymmetrical firing angle modulation for 12-pulse thyristor rectifiers supplying high-power electrolyzers
(IEEE, 2023) Iribarren Zabalegui, Álvaro; Barrios Rípodas, Ernesto; Elizondo Martínez, David; Sanchis Gúrpide, Pablo; Ursúa Rubio, Alfredo; Ingeniería Eléctrica, Electrónica y de Comunicación; Institute of Smart Cities - ISC; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren
This paper presents an asymmetrical firing angle modulation strategy for 12-pulse thyristor rectifiers aimed at supplying high-power electrolyzers, which allows to reduce the size of the passive filter and the static compensator (STATCOM) required to comply with grid harmonic regulations and achieve unity power factor. Usually, 12-pulse thyristor rectifiers follow a symmetric modulation strategy in which the same firing angle is applied to both 6-pulse bridges. In this case, large passive ac-side inductances are required to reduce grid current harmonics, which increase the reactive power consumption and thus the required STATCOM size. However, this paper demonstrates that by applying different firing angles to the two 6-pulse bridges it is possible to comply with the harmonic regulation limits using smaller filtering inductances and therefore reducing the STATCOM size. The methodology to find the optimal firing angle values that should be applied in order to minimize the filtering inductance and the STATCOM size for a given electrolyzer is explained. This strategy is validated by simulation, and results show that the required filtering inductance and the apparent power of the STATCOM can be effectively reduced by 62% and 31%, respectively, using this asymmetrical firing angle modulation.
Open Access
Integration of second-life battery packs for self-consumption applications: analysis of a real experience
(IEEE, 2021) Soto Cabria, Adrián; Berrueta Irigoyen, Alberto; Zorrilla, Pablo; Iribarren Zabalegui, Álvaro; Castillo, Diego H.; Rodríguez Rodríguez, Wenceslao Eduardo; Rodríguez, Adolfo J.; Vargas Requena, Dávid Tomás; Matías Maestro, Ignacio; Sanchis Gúrpide, Pablo; Ursúa Rubio, Alfredo; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren; Institute of Smart Cities - ISC; Ingeniería Eléctrica, Electrónica y de Comunicación; Gobierno de Navarra / Nafarroako Gobernua, 0011–1411–2018–000029 GERA; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa, ReBMS PJUPNA1904
This contribution presents a methodology for the integration of Li-ion batteries discarded from electric vehicle into a collective self-consumption installation, showing the technical feasibility of such battery second use. In this regard, the state of charge (SOC) estimation is a relevant issue for the energy management of the second-life battery. Therefore, a SOC estimator is proposed in this contribution and tested in field. Moreover, the revealed costs analysis allows an economic comparison between the integration of a discarded battery pack in a second-life application or a remanufacture of these packs, thereby selecting the most suitable cells to build second-life batteries. This is a crucial issue for companies focused on the development of second-life batteries. The results obtained after testing the second-life battery pack in a real installation make it possible to extol the benefits of including this type of batteries in a self-consumption system, reaching a self-consumption ratio of 69 % and reducing by 36 % the maximum power peak demanded from the grid.
Open Access
On the impact of high-power grid-connected thyristor rectifiers on the efficiency of hydrogen electrolyzers
(IEEE, 2024-08-30) Iribarren Zabalegui, Álvaro; Barrios Rípodas, Ernesto; Rivera, Marco; Wheeler, Patrick; Sanchis Gúrpide, Pablo; Ursúa Rubio, Alfredo; Ingeniería Eléctrica, Electrónica y de Comunicación; Ingeniaritza Elektrikoa, Elektronikoa eta Telekomunikazio Ingeniaritza; Institute of Smart Cities - ISC; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
This paper investigates the impact of power supply and dc current ripple on the efficiency of water electrolyzers and demonstrates that optimally sized thyristor rectifiers meeting grid power quality regulations can effectively supply high-power electrolyzers with minimal impact on electrolyzer efficiency. Firstly, an equivalent electrical model for the electrolyzer is developed, and the efficiency reduction caused by dc current ripple is analyzed. This is validated by means of experimental data from a 5-kW alkaline electrolyzer operated with both thyristor- and IGBT-based rectifiers. Next, the paper explores the operation of high-power electrolyzers supplied by 6- and 12-pulse thyristor rectifiers complying with grid power quality standards. Results show that with optimal sizing of ac-side source voltage and filtering inductances, these solutions exhibit negligible dc current ripple impact on electrolyzer efficiency. These findings, validated through simulation of a 5.5 MW electrolyzer, highlight the viability of thyristor rectifiers in high-power electrolysis applications, and emphasize the importance of an optimal power supply design and sizing for enhancing water electrolyzers' performance.
Open Access
Modeling and optimal sizing of thyristor rectifiers for high-power hydrogen electrolyzers
(IEEE, 2025-05-01) Iribarren Zabalegui, Álvaro; Barrios Rípodas, Ernesto; Sanchis Gúrpide, Pablo; Ursúa Rubio, Alfredo; Ingeniería Eléctrica, Electrónica y de Comunicación; Ingeniaritza Elektrikoa, Elektronikoa eta Telekomunikazio Ingeniaritza; Institute of Smart Cities - ISC; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
Thyristor rectifiers are currently the most common solution for supplying high-power electrolyzers. These rectifiers typically include a dc inductance, which significantly increases system costs. However, this inductance can be avoided by relying solely on ac-side inductances, required for grid current harmonic filtering, although this approach introduces specific challenges. Traditional analytical models of thyristor rectifiers are unable to determine the electrolyzer operating point for a given firing angle and may lead to incorrect system sizing, ultimately preventing the converter from delivering nominal power. This limitation arises from the fact that existing models are formulated for inductive or constant-current loads, whereas electrolyzers exhibit electrical behavior closer to constant-voltage loads. In this paper, a novel analytical model of 6- and 12-pulse thyristor rectifiers with constant-voltage load is developed. The model enables the analysis and optimal sizing of thyristor rectifiers directly connected to electrolyzers without a dc-side inductance. Its accuracy has been validated through both simulations and experimentally using a laboratory-scale prototype. Furthermore, the model has been applied to optimally size a 12-pulse rectifier supplying a 5.5 MW electrolyzer, demonstrating its suitability for the design of thyristor rectifier systems in industrial-scale electrolysis applications and highlighting its advantages over traditional approaches.
Open Access
Electrospinnig of superhydrophobic nanocomposite films for corrosion protection of aluminum substrates
(2019) Iribarren Zabalegui, Álvaro; Rivero Fuente, Pedro J.; Berlanga Labari, Carlos; Escuela Técnica Superior de Ingenieros Industriales y de Telecomunicación; Telekomunikazio eta Industria Ingeniarien Goi Mailako Eskola Teknikoa
In this work, the electrospinning technique is used for the synthesis of micro/nanofibers using a polymeric precursor with hydrophobic (even superhydrophobic) behaviour such as polystyrene (PS) or polyvinyl chloride (PVC). These electrospun fibers are deposited onto aluminum substrates (6061T6). The effect of varying the different electrospinning deposition parameters (mostly applied voltage and flow-rate) will be exhaustively analyzed in order to optimize the resultant electrospun coatings. Several fiber characterization tests have been performed, including Field Emission Scanning Electron Microscopy (FE-SEM), Atomic Force Microscopy (AFM), Thermogravimetric analysis (TGA), Differential Scanning Calorimetry (DSC), Optical Microscopy (OM) and Water Contact Angle (WCA) measurements. Furthermore, the anti-corrosion properties of these electrospun coatings can be enhanced by the addition of metal oxide nanoparticles (ZnO) that act as corrosion inhibitors. Finally, electrochemical corrosion tests (Tafel and pitting tests) have been performed, showing an improvement in the resultant corrosion resistance of the aluminum alloys coated by the combination of both polymeric films with metal oxide inorganic nanoparticles.
Open Access
Parallel interleaved current source rectifiers for high-power hydrogen electrolyzers and optimal DC inductance design
(IEEE, 2025-03-10) Iribarren Zabalegui, Álvaro; Barrios Rípodas, Ernesto; Balda Belzunegui, Julián; Rivera, Marco; Wheeler, Patrick; Ursúa Rubio, Alfredo; Sanchis Gúrpide, Pablo; Ingeniería Eléctrica, Electrónica y de Comunicación; Ingeniaritza Elektrikoa, Elektronikoa eta Telekomunikazio Ingeniaritza; Institute of Smart Cities - ISC
Due to their single-stage step-down nature, current source rectifiers (CSR) constitute attractive options for supplying high-power electrolyzers. To increase system power rating, parallel configurations can be adopted with interleaved Pulse Width Modulation (PWM) techniques that improve power quality and reduce the size of filtering elements. Optimal design of the output dc inductance is crucial to achieve cost-effective and competitive solutions. However, common design methods for one single CSR do not achieve optimal designs. There are hardly any specific design methods for interleaved CSRs either. This paper analyzes the operation of parallel interleaved CSRs supplying high-power electrolyzers and develops a methodology to optimally size the output dc inductances. In addition, a common mode equivalent circuit is developed to analyze the circulating currents caused by the interleaved operation and calculate the ripple in the inductances. When applied to a 3 MW electrolyzer, the results show that inductance size reductions of up to 69% can be obtained with the proposed methodology.
Open Access
Modelling and operation of 6-pulse thyristor rectifiers for supplying high power electrolyzers
(IEEE, 2022) Iribarren Zabalegui, Álvaro; Barrios Rípodas, Ernesto; Ibaiondo, Harkaitz; Sánchez Ruiz, Alain; Arza, Joseba; Sanchis Gúrpide, Pablo; Ursúa Rubio, Alfredo; Ingeniería Eléctrica, Electrónica y de Comunicación; Institute of Smart Cities - ISC; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren
This paper presents a detailed analysis of a 6-pulse thyristor rectifier aimed at supplying high power electrolyzers. For this purpose, an analytical model of the three-phase controlled rectifier with AC-side inductance and constant-voltage load has been developed. The different operating modes are identified and characterized. The derived equations are then combined with the electrical model of the electrolyzer, which allows to predict the operating point of the system. This model may serve as a useful tool for dimensioning thyristor rectifiers when operating with high power electrolyzers.