High-power electrolyzer characterization via smart power converters

Abstract

This paper presents a novel concept to extract electrolyzer characteristics using advanced power converters. By synthesizing current and voltage perturbations it becomes possible to perform measurements that are comparable to electrochemical impedance spectroscopy, a powerful technique that is now still mostly confined to laboratories. Since the new concept is more limited in terms of frequency, we have investigated in what frequency range maximum phase shifts and impedances can be observed. For traditional and advanced alkaline electrolyzers this is from hundreds of millihertz to hundreds of Hertz, which is compatible with the capabilities of advanced power converters. With a combined power supply-electrolyzer model we show that it is indeed possible to obtain the same type of information as with electrochemical impedance spectroscopy. Biggest challenge lies in the accurate measurements of impedances that are in the order of microohms. The presented concept can potentially be used for stack or even cell lifetime monitoring and can facilitate predictive maintenance.