Research Information System
International Journal of Hydrogen Energy, vol.229, 2026 (SCI-Expanded, Scopus)
AbstractThis paper proposes a robust phase locked loop (PLL)-free control approach for integrating vehicular proton exchange membrane (PEM) fuel cells into single-phase grids, specifically focusing on operation under potentially distorted grid voltage conditions. The proposed PLL-free control scheme eliminates the need for conventional PLL, significantly reducing computational complexity and enhancing system stability, particularly under weak grid conditions. It achieves robust synchronization and highly accurate reference current generation in the dq-frame by employing Second-Order Filter (SOF) to extract the fundamental voltage components from the measured grid voltage, even when distorted. Compared to conventional PLL-free method, the proposed architecture shows better performance, achieving a dramatic reduction in total harmonic distortion (THD). For six operating cases, the THD is maintained in a range between 1.04% and 3.11%, while the conventional method exhibited values as high as 10.79%. This confirms the system's compliance with grid standards and enhanced current quality under non-ideal grid scenarios.