An Enhanced Grid-Forming Control Strategy for DC-Coupled Alkaline Water Electrolyzers

Recent years have seen the research on the participation of Alkaline water electrolyzers (AWEs) in power grid regulation gained significant traction. In particular, the participation of AWEs in grid-forming (GFM) services is precisely an urgent research topic at present. However, regarding the involvement of AWEs in GFM services, existing studies are typically limited to single AWE units or rely on communication for controlling multiple AWEs. Nor have they considered the capacity variation characteristics of AWEs. Furthermore, the unique topologies of DC-coupled AWE systems require special consideration. To address these issues, this paper proposes an enhanced GFM control strategy for DC-coupled AWE systems. Specifically, the proposed control scheme includes two key improvements. First, a temperature-driven droop control is employed to enable coordinated operation among individual AWE units. Second, an improved DC-link voltage synchronized control (IDVSC) is proposed for the voltage source converter (VSC). Furthermore, the proposed strategy is fully decentralized, allowing both AWE units and the VSC to provide GFM services. Finally, the effectiveness of the proposed strategy is validated through simulation and experimental results.