Hybrid-electric propulsive systems sizing and performance evaluation tool for aircraft and UAV

This paper aims at evaluating the performance of hybrid-electric propulsion systems through a preliminary and low-cost computational sizing tool for aeronautical vehicles. In particular, we analyze (i) a hybrid-electric system composed of fuel cell and supercapacitors, tested on small scale applications, such as UAVs, and (ii) a system made of a traditional thermal engine coupled with electro-chemical batteries, typical of large scale systems, such as regional transport aircrafts. We show how an hybrid-electric power system composed of a fuel cell and a supercapacitor can be used to power a multirotor UAV. We observe an improvement of the manoeuvrability and the performance compared to a battery-power drone, thanks to the fastest response of the supercapacitor to the load peaks, and to the down-sizing of the fuel cell, which is sized to supply the average power demand only. Next, we analyze the hybrid-electric resizing of an ATR 72-600 with parallel-hybrid configuration of battery and fuel tank and we highlight the necessity of an optimal hybridization level, to be found through a multi-objective optimization, in order to minimize the fuel consumption and to contain the increase in take-off weight.