Optimal design and sensitivity analysis of a dual active bridge converter for electrolyzer-based hydrogen production

The large-scale deployment of electrolyzers for green hydrogen production is hindered by challenges related to efficiency, power density, and cost-effectiveness across a wide range of operating conditions. To address these challenges, this work presents the design and experimental validation of a high-frequency gallium nitride field-effect transistor (GaNFET)-based inductance-capacitance dual-active-bridge (LC-DAB) converter tailored for electrolyzer applications. An analysis of load-dependent current variations first guides the optimal selection of resonant inductance and capacitance to minimize output power fluctuation. To enhance dynamic performance, a primary-current secondary-voltage synchronization (PCSVS) modulation technique is developed for electrolyzer application. This technique suppresses circulating currents and improves power transfer by synchronizing the resonant current with the secondary-side voltage. The design incorporates a detailed sensitivity analysis of converter parameters and a mathematical model of the electrolyzer to ensure stable operation. The proposed architecture and control strategy are validated through detailed simulations and a 1.5 kW laboratory prototype. Operating from a 37.5 V input to a 10-30 V output at output currents of up to 50 A, the prototype achieves a peak efficiency of 96.2%, supported by a comprehensive loss analysis. The results demonstrate a highly efficient and responsive power conversion solution tailored for modern electrolyzer systems.