Energy management and control strategies for proton exchange membrane fuel cells in transportation

Proton Exchange Membrane Fuel Cells (PEMFCs) are a promising technology for clean energy conversion, particularly in transportation applications, but their efficient operation requires addressing multiple challenges including water and thermal management, power allocation under degradation, and hybrid energy system control. This thesis is organized into five chapters, including an introduction and conclusion, with three core chapters focusing on key aspects of PEMFC system optimization. The first technical chapter investigates water and thermal management in PEMFC stacks, proposing a novel control framework that integrates a supervisory Model Predictive Controller (MPC) with local PID controllers for humidity regulation. Introducing the concept of Feasible Humidity Plots (FHP), this approach defines operational bounds for anode and cathode relative humidities, enabling robust water balance and temperature control. Simulation results demonstrate effective setpoint tracking and disturbance rejection, with resilience to model uncertainties and fuel cell aging. Building on this foundation, the second chapter develops a real-time optimization strategy for power sharing between two PEMFC stacks, accounting for degradation effects characterized by a time-varying electron transfer coefficient estimated via RLS-Kalman filtering. Incorporating hydrogen crossover impacts, the proposed method optimizes efficiency and hydrogen consumption, outperforming conventional equal distribution and daisy chain strategies. The framework's adaptability to multiple stacks and objective functions is validated through extensive simulations. The third core chapter addresses energy management in Fuel Cell Hybrid Electric Vehicles (FCHEVs), integrating multiple PEMFC stacks with a battery. A two-layer hierarchical control scheme is introduced, combining a Dual-Rate Economic MPC for splitting power between the slow fuel cell system and fast battery, with a secondary optimizer for degradation-aware stack power allocation. Simulation results confirm significant reductions in hydrogen consumption compared to benchmark strategies. Collectively, the results presented throughout the thesis advance the state-of-the-art in PEMFC system control and optimization, promoting sustainable and efficient fuel cell applications in both industrial and transportation sectors.