Experimental Validation of DC-link Based Voltage Control Framework for Islanded Hydrogen DC Microgrids

The integration of hydrogen technologies into islanded DC microgrids presents significant challenges in maintaining voltage stability and coordinating power flow under highly variable renewable energy conditions. This paper proposes a novel DC-link voltage control (DCVC) framework that incorporates adaptive droop control and autonomous operation algorithms to regulate fuel cells, electrolysers, and battery systems in a coordinated manner. Unlike conventional fixed-gain or priority-based methods, the proposed adaptive control dynamically adjusts the droop coefficient in response to voltage deviations, enhancing system stability and responsiveness. The control framework is validated on an industry-standard hydrogen DC microgrid platform developed at Griffith University, featuring real-time implementation on a Raspberry Pi controller and comprehensive integration with solar, wind, wave, and hydrogen energy sources. A small-signal stability analysis confirms that the proposed control ensures asymptotic voltage convergence under dynamic operating conditions. Experimental results across five case studies demonstrate that the proposed DCVC strategy ensures fast transient response, minimises overshoot, and maintains the DC-link voltage near the nominal 380 V under varying load and generation scenarios. The framework facilitates flexible energy sharing while ensuring safe hydrogen production and storage. It is also compatible with low-cost, open-source hardware, making it a scalable solution for remote and off-grid energy applications.