Coordinated control strategy of hydrogen production system in DC microgrid considering operating states of electrolyzer

Abstract

<p>The utilization of clean energy for hydrogen production is a critical approach to reducing carbon emissions and efficiently absorbing renewable power generation. For off-grid water electrolysis hydrogen production, a coordinated control strategy for ‘wind-storage-hydrogen’ DC microgrid is proposed in present work, accounting for the wide power range of the electrolyzer. This strategy addresses issues of system instability and suboptimal power distribution caused by wind power fluctuations and variations of electrolyzer states. Firstly, the structure of the DC microgrid hydrogen production system is defined, and operating modes are segmented based on bus voltage to enable coordinated operation among the ‘wind-storage-hydrogen’. Secondly, an adaptive fuzzy droop control is introduced, dynamically adjusting the slope and endpoints of the droop curve according to the electrolyzer’s key states and operating characteristics. This achieves adaptive responses to electrolyzer state changes across different load range. Then, a coordination sub-strategy for ‘storage-hydrogen’ is designed based on bus voltage deviation, which suppresses bus voltage fluctuations and ensures efficient electrolyzer operation by optimizing energy distribution between energy storage and hydrogen production during trough period. The simulation results indicate that the stability of the system bus voltage and electrolyzer operation is improved significantly. Additionally, the power distribution scheme is optimized. When the electrolyzer operates under low-load conditions, it can achieve a 9.6% increase in its efficiency while maintaining voltage deviation below 4.2%.</p>