Integrated co-simulation of PEM fuel cell systems for automotive applications: modeling, coupling, and system behavior

Abstract

Detailed stack models and dynamic balance-of-plant (BoP) models each capture important aspects of proton exchange membrane (PEM) fuel cell systems but are limited when applied independently. While detailed stack models are computationally demanding for system-level investigations, reduced-order system models often lack the physical fidelity required to accurately represent electrochemical processes and their interaction with auxiliary components. To address this gap, this work presents a modular cross-tool co-simulation framework that couples a physics-based PEM fuel cell stack model with a dynamic BoP model. In contrast to existing co-simulation approaches focusing primarily on stack-internal behavior, the framework enables a consistent analysis of the interactions between stack operation and BoP dynamics, linking electrochemical, thermal, and auxiliary losses within a unified system-level environment. The framework is implemented in AVL CRUISE™ M and MATLAB ® and evaluated under representative transient operating conditions. Solver synchronization and coupling strategies are assessed with respect to numerical stability, simulation accuracy and computational performance. The results demonstrate stable and accurate co-simulation while achieving a real-time factor of 1.74, making the framework suitable for real-time applications. Furthermore, the integrated loss analysis reveals that the overall system efficiency decreases from 49.6% at low load to 38.8% at high load, with the contribution of individual loss mechanisms strongly depending on the operating conditions. The proposed framework provides a flexible basis for transient system analysis, efficiency optimization, and future applications such as control strategy development, hardware-in-the-loop testing, and digital twin implementations.