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 (TRs) and diode bridge rectifiers with DC-DC converters. Interestingly, active front-end (AFE) power converters have not garnered much attention. In addition, critical aspects, such as the impact of nonideal grid behaviors (e.g., voltage harmonics or voltage variations) on the sizing of power devices, have not been addressed. This article aims to fill this gap by presenting a comprehensive comparative analysis of four distinct power converter topologies: TRs, diode rectifiers (DRs) with DC-DC, AFE power converters, and AFE power converters with DC-DC. This analysis covers the 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.