Improved Passivity-Hamiltonian Control Law for Multi-Stack Fuel Cell System for DC Microgrid Applications

Proton Exchange Membrane Fuel Cells (PEMFCs) are gaining a lot of attention in sustainable energy systems, particularly in high-power applications by using Multi-Stack Fuel Cell Systems (MFCS). When integrated into DC microgrids, MFCS offer enhanced efficiency and stability but face challenges due to constant power loads (CPLs) and nonlinear dynamics. This paper proposes an Improved Passivity-Hamiltonian Control Law (PHCL). The control design integrates adaptive damping, multi-integral compensation, and Lyapunov-based stability to achieve robust DC-link voltage regulation and balanced current sharing among stacks. A novel integral scheme further ensures equal power distribution despite voltage mismatches or degradation. The proposed approach is validated experimentally on a hardware platform comprising two PEMFC stacks interfaced with boost converters. These obtained results confirm the robustness and practicality of the improved PHCL for MFCS-based DC microgrid applications