BUSCADOR RECOLECTA

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., This work is part of the projects PID2022-142791OB-I00 and PID2022-139914OB-I00 funded by MICIU/AEI/10.13039/501100011033/ and by 'ERDF/EU', and has also been supported by the Public University of Navarra under a Ph.D. scholarship. It has also been supported by Ingeteam Power Technology. The authors also thank the Agencia Nacional de Investigación y Desarrollo (ANID) FONDECYT Regular grant number 1220556, the Centre for Multidisciplinary Research on Smart and Sustainable Energy Technologies for Sub-Antarctic Regions under Climate Crisis ANID/ATE220023, Fondap SERC 1522A0006 and IRCF 24932270 project from the University of Nottingham.

In grid-forming mode (GFM) doubly-fed induction generator based wind turbines connected to the grid, the converter connected to the rotor side is normally responsible for providing the grid-forming characteristics, while the grid-side converter commonly controls the DC-bus voltage thanks to a current control loop implemented in a rotating reference frame. The angle for the rotating reference frame is obtained by means of a phase-locked loop, which synchronizes the converter with the grid. However, this synchronization loop can introduce stability problems in weak grids. This paper proposes to synchronize the grid-side converter by means of the power synchronization loop of the GFM control of the rotor-side converter. This eliminates the need to use of a specific phase-locked loop, improving small-signal stability as demonstrated in the small-signal stability analysis performed in this paper., This work is part of the Projects PID2022-142791OB-I00 and TED2021-132604B-I00, funded by MICIU/AEI /10.13039/501100011033, by ERDF/UE and by the European Union NextGenerationEU/PRTR. It has also been supported by Ingeteam Power Technology.