An efficiency-oriented hierarchical energy management strategy for renewable electric-hydrogen systems with adaptive multi-stack PEMFC activation

Abstract

The growing integration of renewable energy sources requires efficient management strategies for electric-hydrogen coupled systems. Conventional single fuel cell configurations suffer from limited power capacity and poor efficiency under dynamic conditions, while existing power allocation methods for multi-stack fuel cell systems often neglect the coordinated effects of battery state of charge and hydrogen storage conditions. This study proposes a hierarchical energy management strategy for electric-hydrogen coupled multi-stack proton exchange membrane fuel cell (PEMFC) systems, combining a supervisory state-machine layer with an equipment-level control layer. The upper layer determines the optimal operating state by considering residual power demand, lithium battery state of charge, and hydrogen storage state, and dynamically allocates the number of active fuel cell stacks. The lower layer implements the corresponding commands through individual device controllers to coordinate photovoltaic generation, energy storage, hydrogen production, and fuel cell operation. By keeping PEMFC operation near its high-efficiency region, the strategy reduces unnecessary stack activation and improves stability under variable operating conditions. MATLAB/Simulink simulations show that the proposed strategy achieves smoother power transitions, higher fuel cell efficiency, and stable operation under external disturbances. A comparison against two representative literature-based strategies, an adaptive power allocation method and a fuzzy logic-based approach, further confirms higher PEMFC efficiency and faster convergence, raising PEMFC operating efficiency from approximately 43% to 48.21% by keeping active stacks near the optimal operating point of 10 kW. These results indicate that the proposed approach provides an effective energy management solution for renewable-based electric-hydrogen integrated energy systems.