DC–DC Multi-Arm Interleaved Zeta Converter With Parallel Switch Modulation for Renewable-Powered Electrolyzers

This manuscript presents a DC-DC Multi-Arm Interleaved Zeta Converter with Parallel Switch Modulation for renewable-powered electrolyzers. The proposed converter features low current and voltage ripple, reduced power losses, and minimized magnetic volume. The use of parallel switches combined with an interleaved PWM technique simplifies the design and enhances performance without requiring inductors proportional to the number of arms. Key advantages include electrolyzer voltage and current ripple frequencies six times higher than the switching frequency, as well as output capacitor current ripple frequencies also six times higher. In addition, the inductor and coupling capacitor current ripple frequencies are twice the switching frequency. This behavior enables a significant reduction in the volume and mass of passive components, thereby improving power density. The paper presents the steady-state operating principles under continuous conduction mode, design guidelines, mathematical derivations, and a comparative analysis with state-of-the-art converters. A 6-kW proof-of-concept prototype was experimentally tested with a DC bus voltage of 480 V and an electrolyzer voltage of 250 V, demonstrating a peak efficiency of 98.16%, supported by experimental results and an accompanying demonstration video.