Hierarchical Optimization Strategy for Variable Altitude Net Power of Fuel Cell Systems Considering Intercooler Energy Consumption

Driven by low-carbon policies, the fuel cell (FC) vehicle industry is embracing rapid development opportunities. This study focuses on commercial vehicle FC systems to conduct power optimization research under variable altitude environments, aiming to resolve the significant net power attenuation issue in altitude-changing scenarios for commercial vehicles. Models for the FC air supply system and atmospheric environment were established, revealing power attenuation with altitude. Analysis characterized compressed air temperature and intercooler thermal loss across altitudes, constructing a four-dimensional mapping of load, air supply, stack performance, and parasitic power. Targeting maximum net system power, an optimal offline algorithm determined ideal air supply parameters under varying altitudes. A dual-degree-of-freedom hierarchical online optimization architecture was designed, proposing an altitude-adaptive strategy integrating offline calibration with online correction. The results show that compared with conventional strategies, 2.02% to 9.07% power enhancement at 4000m altitude. Under custom variable-altitude conditions, the proposed strategy achieves 1.53% to 3.29% power optimization superiority over comparative methods. Finally, the real-time performance of the optimization strategy was validated through hardware-in-the-loop (HIL) testing platform experiments.