Symmetrical Virtual 48-Pulse Rectifier with Hybrid Multi-Mode Pulse Multiplication for High-Current-Density Hydrogen Electrolyzers

The integration of renewable energy with electrolytic hydrogen production presents a promising pathway for reconciling generation-demand imbalances and reducing carbon-intensive hydrogen costs. However, existing power conversion systems suffer from critical limitations including excessive harmonic distortion, prohibitive output current ripple, and inadequate fault tolerance under high-current operation. This paper proposes a novel virtual 48-pulse rectifier topology incorporating modular passive pulse-multiplication circuits (PPMCs) to address these challenges. The key innovation lies in deploying symmetric PPMC modules at the DC side of a dual 6-pulse rectifier pair, which strategically synthesizes multi-level current waveforms through passive component interactions. This configuration achieves three key merits: i) Unprecedented power quality with input THD <3% and output ripple <1.5%; ii) Cost-effective scalability requiring only few of additional passive components compared to baseline 12-pulse systems; iii) Inherent fault tolerance via parallel redundancy, maintaining functionality during single-module failures. The effectiveness of the proposed rectifier in electrolytic hydrogen production is demonstrated through validation with a 1.2 kW experimental prototype.