Comparative analysis of thyristor-based and transistor-based rectifiers for PEM water electrolysis

Abstract

Hydrogen is an important industrial gas for clean fuel, power-to-gas energy storage, and chemical production. In large-scale electrolysis systems with a high direct current supply, power rectifiers are important components to connect to the main power grid. Currently, Thyristor-based topology is most commonly used for large-scale industrial proton exchange membrane (PEM) water electrolysis applications due to its maturity. However, this topology cannot always satisfy the main grid requirements and instead lead to higher specific energy consumption per kilogram of hydrogen produced. Instead, the transistor-based topology is more promising to reduce the total system cost. In this research, 6-pulse thyristor-based and transistor-based topologies are compared and investigated to improve the power quality for a 20 MW PEM water electrolyzer in Air Liquide's Bécancour plant. We first built a Matlab/Simulink model to simulate the water electrolysis system. Then, we compared the power quality parameters with the plant measurement.