| Popis: |
This paper investigates the effectiveness of a parallelized low-cost DC/DC converter array within the power distribution system of a hybrid-propulsion multi-rotor unmanned aerial vehicle (UAV). In conventional multirotor UAVs, lithium polymer (LiPo) batteries are almost exclusively used as power sources. Since they are characterized by rather low energy density (over 40 times lower) compared to gasoline, aircraft’s typically high-power demand results in limited flight duration (typically 10 to 30 minutes). Therefore, a hybrid power plant, comprising a lightweight two-stroke spark-ignited internal combustion engine (ICE) driving a brushless direct current generator (BLDCG) and a high-power lithium-polymer battery may offer noticeable advantages in terms of range and flight autonomy for UAVs. Such a configuration can facilitate ICE operation at near-optimal fuel efficiency, while at the same time enabling fast aircraft manoeuvring wherein battery covers for peak power demands from the propulsion system. By employing centralised control of engine-generator set output power system, the direct-current bus voltage can be sustained within required limits for a successful flight of the multirotor UAV. For different power demand conditions (such as hovering, forward flight and complex manoeuvring), such a power system provides active load sharing, wherein aircraft hovering power requirements are covered by the engine-generator set, while peak power demands are covered by the battery. The resulting direct-current bus voltage and current control systems have been verified by means of detailed computer simulations and experimentally on the hybrid propulsion system laboratory setup. |
