Modeling and Stability Analysis of Fuel Cell-Based Marine Hybrid Power Systems

This article proposes a framework for stability analysis of hydrogen fuel cell-based hybrid power systems (HPSs) for zero-emission propulsion. An analytical model is developed, and a comprehensive modal analysis is performed to address the HPS dynamic interactions. Sensitivity analysis assesses the impact of operating conditions, control parameters of the governor and converter controllers, and different control strategies. The case studies focus on how the parameters of the HPS state variables are coupled with the HPS modes through participation factors (PFs), thereby emphasizing which system state participates in determining the system's dynamics. The modal analysis characterizes the influence of control parameters on poorly damped modes and enables the expansion of the stable operating region of the HPS by appropriate control parameter selection. The results indicate a notable impact of the voltage-control loop parameters on the system stability, a strong coupling between the subsystems' current state variables and dc bus voltage dynamics, and a strong coupling between the governor dynamics and the FC current state. In addition, the study demonstrates a PF of 0.9 between the dc bus voltage and the HPS's critical modes within 15% deviation by changes in the voltage controller's proportional gain. Finally, analytical analysis and time-domain simulations are validated with a real-time hardware-in-the-loop (HIL) test setup.