Investigating voltage ripple effects in PEM electrolysis: test protocol development and experimental characterisation

Abstract

PEM water electrolysis is a key technology for producing high-purity hydrogen with a compact design. However, the widespread adoption of PEM electrolysers faces challenges such as the high cost associated with the power supply. Improving electrolyser efficiency is critical to reducing these costs and making the technology more competitive. Element One Energy AS is developing a more cost-effective PEM electrolyser which will be powered by inductive power transfer technology. This approach introduces high-frequency voltage ripple, which can cause significant efficiency losses. While existing research has explored the effects of ripple in PEM electrolysis, studies focusing on high-frequency ripple effects are still limited.

This thesis is centered on designing and developing a testing protocol to evaluate the effects of high-frequency voltage ripple on PEM electrolysis. It encompasses the development of a Python program to control the power supply during testing, the creation of a ripple circuit to replicate voltage ripple conditions in a controlled environment, and the experimental characterisation of ripple voltage effects using a resistor as a stand-in for the electrolyser cell.

The designed ripple circuit successfully generates two distinct ripple waveforms at 720 Hz and 120 kHz which can be utilised for further investigation of voltage ripple effects on PEM electrolysers. The ripple waveforms are influenced by both the power supply and MOSFET behaviour. While using a resistor in place of the faulty electrolyser cell provided preliminary insights, the study emphasises the need for improved ripple circuit design to ensure reliable characterisation of ripple effects on PEM electrolysers.