Control Strategy for Hydrogen Production System using HTO-based Hybrid Electrolyzers

Renewable energy-based water electrolysis for hydrogen production is an effective pathway to achieve green energy transition. However, the intermittency and randomness of renewable energy pose numerous challenges to the safe and stable operation of hydrogen production systems, with the wide power fluctuation adaptability and economic efficiency of electrolyzers being prominent issues. Hybrid electrolyzers combine the operational characteristics of proton exchange membrane (PEM) and alkaline electrolyzers, leveraging the advantages of both to improve adaptability to wide power fluctuations and economic efficiency, thereby enhancing the overall system efficiency. To ensure coordinated operation of hybrid electrolyzers, it is essential to consider their startstop characteristics and the impact of hydrogen to oxygen (HTO) concentration on the hydrogen production system. To achieve this, we first discuss the operating characteristics of both types of electrolyzers and the in fluence of system parameters on HTO concentration. A control scheme for hybrid electrolyzer systems consid ering HTO content is proposed. By analyzing the electrolyzer efficiency curve, the optimal efficiency point under low power operation is identified, enabling the electrolyzers to operate at this optimal efficiency, thus enhancing the efficiency of the hybrid electrolyzer system. The implementation of a dual-layer rotation control strategy effectively balances the lifecycle loss of the electrolyzers. Additionally, reducing the pressure during startup broadens the startup range of the hybrid electrolyzer.