Hierarchical power management of hydrogen fuel cell hybrid UAM system: Thermal performance analysis and case study

This study proposes a hierarchical power management system (PMS) for a hydrogen fuel cell-battery-supercapacitor hybrid Urban Air Mobility (UAM) system, considering both thermal behavior and energy management under dynamic flight conditions. Due to the distinct dynamic and energy characteristics of each power source, effective coordination is required to handle rapid load fluctuations while maintaining thermal stability and efficiency. The supercapacitor compensates for high-frequency power variations, while the fuel cell and battery supply steady-state power using three control strategies: Rule-based Control (RBC), State Machine Control (SMC), and Fuzzy Logic Control (FLC). System performance is evaluated using a multi-criteria decision-making (MCDM) method based on hydrogen consumption, battery state of charge (SoC), thermal response, parasitic energy consumption and lifetime. The results demonstrate that FLC achieves the best overall performance by reducing temperature fluctuations and improving energy efficiency under dynamic conditions. SMC provides advantages in hydrogen consumption, whereas RBC exhibits the lowest overall performance due to limited adaptability. These findings indicate that the proposed hierarchical PMS effectively coordinates multiple energy sources while simultaneously improving thermal stability and energy efficiency, demonstrating its suitability for dynamic UAM operating conditions.