Comparative analysis of hybrid fuel cell powertrain architectures for orchard tractors using hardware-in-the-loop technique

Fuel cell systems represent a possible solution to improve the sustainability of vehicles requiring high endurance and compactness. Three different powertrains for an orchard tractor are proposed. The proposed systems feature the same fuel cell unit, but different auxiliary sources: a battery pack, a supercapacitor module and a hybrid unit comprising both. Furthermore, to make a fair comparison, the three architectures are designed considering the same overall volume. After defining the architectures, different rule-based strategies, namely power follower and fuzzy logic strategies, are defined to determine the power split among the different sources. Then, the three architectures are tested using a scaled Hardware-in-the-loop test bench according to typical work scenarios. The load profiles are derived from experimental data collected on a commercial orchard tractor. The architectures and energy management strategies are compared considering fuel economy and components durability. Analysing the results, the topology featuring the battery pack as additional power unit shows the higher lifetime expectancy for the fuel cell system, with an improvement ranging from +20 % to +200 % compared to the other two topologies. On the other hand, the differences in terms of fuel economy are considered not relevant compared to the differences in durability.