Robust Coordination Control Strategy for Large-Scale Alkaline Water Electrolyzers Driven by Renewable Energy

The multiparalleled alkaline water electrolyzers (AWE) system driven by renewable energy has received increasing attention from researchers. However, time-varying renewable energy sources can affect AWEs’ temperatures, and thus change their capacity. Under this condition, if the constant droop control coefficient is still adopted, it is prone to result in inaccurate power sharing. Furthermore, the changes in AWE's parameters can worsen the control performance of the traditional PI controller. Unfortunately, these are seldom considered in AWE control system design in the existing literature. Thus, there is an urgent need to conduct an in-depth investigation into the AWE system control strategy under the temperature fluctuation condition. In this article, a droop coefficient adjustment and self-tuning fuzzy PI controller (STFPIC)–based adaptive droop control strategy is proposed. Unlike the conventional droop control where the droop coefficients are fixed, the droop coefficients here are adjusted according to the AWE temperature measured in real time. The core of the STFPIC is the fuzzy domain which is modified according to the AWE temperature. Finally, based on an electrolysis hydrogen experimental platform, which includes the AWEs and the proton exchange membrane (PEM) electrolyzer, the effectiveness of the proposed control strategy is verified. The experimental results show that the proposed control strategy can not only promote accurate power distribution and improve the dynamic performance of AWEs but also have a positive impact on PEM electrolyzers.