It is a current trend that the grid-connected DC-coupled hydrogen production system (GDHPS) participates in grid regulation within the framework of the energy transition strategy. On one hand

it should provide frequency support to the grid to the greatest extent possible. On the other hand

it needs to ensure a reasonable power distribution among electrolyzers. In the existing literature

this issue has been scarcely considered. To fill this gap

this paper focuses on alkaline water electrolyzers (AWEs) and proposes a novel frequency support control strategy for the GDHPS. Specifically

there are three improvements in this control strategy. First

An adaptive virtual thermal resistor control strategy is proposed. The control system updates AWE model periodically

and calculates the real-time droop coefficient in combination with the AWE's temperature. Second

a frequency response mechanism is proposed. Third

the virtual inertial response mechanism is introduced to improve the dynamic performance. The proposed control strategy realizes completely decentralized control and reasonable power sharing among AWEs within wide temperature range

and also provides frequency support for the grid. The proposed control strategy is verified in the Matlab/Simulink platform and an electrolysis hydrogen experimental platform.