Powertrain Model Improvement for Hybrid-Electric Regional Aircraft

This paper deals with the definition of an improved powertrain model for hybrid-electric aircraft. It is well known that powertrain equations are one of the most convenient tools for modelling the propulsion system at aircraft level, when it comes to hybrid architectures characterized by more than a single propulsive source. However, for a reliable implementation of a robust optimization algorithm for the hybridization parameters, the designer should consider some singularity points related to certain non-physical configurations depending on the operating mode. In this work, singularities are firstly identified by analyzing the operating modes, then a solving strategy is reported. Another crucial aspect is the correct design and simulation of battery behavior. In a broader perspective, the high-level objective of the activities related to powertrain model is to assess a possible fuel saving for regional turboprops using e-storage units as secondary power source. In this respect, preliminary results in terms of flight performance referred to a regional aircraft similar to ATR42 are presented and discussed. The authors conclude that a block fuel saving up to 51% for the typical mission is possible with a battery specific energy of 500 Wh/kg and when the benefits of aero-propulsive interaction are fully exploited.