POWER MANAGEMENT SUPPLY OPTIMIZATION FOR HYBRID-ELECTRIC REGIONAL AIRCRAFT

This paper presents a performance analysis of a regional hybrid-electric aircraft equipped with a parallel powertrain. The main focus is given to the role of the power supply split between the electric and thermal power throughout the mission. The performance analysis is carried out by using an in-house design code integrating the main multidisciplinary features of aircraft conceptual design and hybrid-electric propulsion integration. An optimization framework is set up for the identification of the optimal power management strategy, in terms of shares of thermal and electric supplied power in the different stages of the mission; the objective is to minimize the fuel consumption. The power supplied by the thermal engine, modeled as a piecewise function of the time, is considered as an optimization variable; a parametric study on the number of intervals composing this function is performed to search the optimal shape of the power supply profile. The optimization framework is used with a dual purpose: to perform an analysis of the aircraft performance varying range and maximum take-off weight, and to identify the optimal electrical and thermal power profiles to minimize fuel consumption. The results show that hybrid-electric propulsion introduces substantial gains at short ranges, with near-zero fuel consumption up to 400 nm, whereas only a 7.5% fuel reduction is achieved with respect to a full-thermal state of the art reference considering ranges of 800 nm. A simple three-stage profile for the power supply function, i.e. for climb, cruise and descent, has been found as enough to optimize the power split between thermal and electric power for the mission.