Comparative Analysis of Power Converter Topologies for Hydrogen Electrolyzers

Power electronic converters are essential for connecting high-power electrolyzers to ac grids. The existing literature on comparative analyses of AC-DC power converters for electrolyzer applications is often limited to Thyristor rectifiers and Diode bridge rectifiers with DC-DC converters. Interestingly, Active Front End power converters have not garnered much attention. Additionally, critical aspects such as the impact of non-ideal grid behaviors (e.g., voltage harmonics or voltage variations) on the sizing of power devices have not been addressed. This paper aims to fill this gap by presenting a comprehensive comparative analysis of four distinct power converter topologies: Thyristor Rectifiers; Diode Rectifiers with DC-DC; Active Front End power converters; and Active Front End power converters with DC-DC. This analysis covers aspects related to ac (grid) and dc (electrolyzer) power quality, effects due to grid voltage variations and harmonics, filter requirements, component sizing, aging of electrolyzer, cost and efficiency.