Power Allocation Strategy for Hybrid Electric Vehicles With a Heterogeneous Dual Fuel‐Cell System

ABSTRACT To address power‐demand fluctuations in fuel‐cell hybrid electric vehicles (FCHEVs) and the resulting trade‐off between hydrogen economy and fuel‐cell dynamic stress, this paper proposes a two‐layer power‐allocation strategy for a heterogeneous dual‐stack fuel‐cell system. The hybrid powertrain consists of a 75 kW main stack, a 25 kW auxiliary stack, a traction battery, and a supercapacitor. Wavelet packet transform (WPT) separates the demanded power into low‐, medium‐, and high‐frequency components, which are allocated to the fuel‐cell system, the battery, and the supercapacitor, respectively. The upper layer performs offline optimization using improved particle swarm optimization (IPSO) to determine steady‐state stack power references based on normalized hydrogen consumption and stress‐proxy objectives. The lower layer performs online reference tracking using model predictive control (MPC) while satisfying power and ramp‐rate constraints. Simulation results obtained in MATLAB/Simulink under CLTC‐P, WLTC, and UDDS cycles demonstrate consistent performance trends. Under CLTC‐P and WLTC, the proposed strategy reduces hydrogen consumption by 20.83% and 20.00%, respectively, compared with the heterogeneous rule‐based benchmark. Meanwhile, the corresponding mean fuel‐cell power ramp rates decrease from 6.80 to 2.70 kW/s and from 7.50 to 3.10 kW/s. These results indicate simulation‐level improvements in hydrogen economy and fuel‐cell power smoothing.