Parallel hybrid propulsion system with integration of designed electric machine for medium altitude long endurance UAV.

Abstract

Unmanned Aerial Vehicles (UAVs) are commonly used in several areas such as military and civilian applications and are getting popular day by day. They have classifications based on their range, total mass and altitude. According to their classification, they have different topologies about propulsion systems. Especially beyond Middle Altitude Long Endurance (MALE) class, they have conventional propulsion systems which is powered by internal combustion engines (ICEs). Nevertheless, the low efficiency rate and detrimental environmental impact of these propulsion systems have prompted the search for more efficient and environmentally friendly propulsion components. Electrical machines are regarded as a promising alternative for powertrain applications, given their high efficiency rate and environmentally friendly characteristics. Prototypes and operational applications have been observed in other transportation vehicles, further substantiating their potential. There are different topologies for hybrid and full electric propulsion systems, but they should be considered with respect of operational requirements of UAVs. Long endurance and range are required especially for MALE class UAVs, and it couldn't achieve with full electric propulsion models because of current battery technology. To address this issue, hybrid propulsion systems represent a promising avenue for resolution. In this study, the MALE class UAV, which is currently in use in the field, has been selected as a case study for the implementation of a hybrid propulsion system. This is because there is currently no known application of hybrid propulsion in this UAV model, which is equipped with an ICE. The results demonstrate that the parallel hybrid propulsion system has enhanced the performance of the existing system.