Autonomous Electrical Power System for Multi Role Transport Tanker Aircraft 2012-01-2192

Today's civil airliners integrate electrical power capability properly sized to supply the growing demands of modern aircraft systems, that are more electrical than ever.

The conversion of civil aircraft into a military derivative aircraft faces the challenge of rearranging the available generation capability to feed the new power-hungry military systems while at the same time minimizing the impact on certification of the base aircraft for use on civil operations. This challenge is particularly difficult when the new military systems demand high peak power consumption, as in the case of the conversion of a civil airliner into a military Multi-Role Transport Tanker aircraft with high performance multipoint refueling capabilities. In fact the selection of the type of actuation (either electrical or hydraulic) for the refueling systems is heavily conditioned by the excess of either electrical or hydraulic power available in the base aircraft.

The A330MRTT Multirole Transport Tanker from Airbus Military uses electromechanical actuation for all the refueling actuation systems, including underwing Pods, Fuselage Refueling Unit and Boom actuation and control systems.

This paper proposes a new autonomous electrical system for supplying the Air to Air Military refueling systems (underwing pods, fuselage refueling unit and boom system) with no power demand to the base aircraft electrical system. Furthermore, this proposed architecture could even provide additional power to the base aircraft in case of emergency operation when the military refueling systems are not operated.

The new proposed architecture integrates power generation capability within the installed refueling systems, energy conversion to the proper distribution level, energy recovery from the refueling systems, energy storage into a battery system and energy distribution to internal military consumers. The power generation capability of the Air to Air Refueling (AAR) autonomous electrical system covers the average power demand of all simultaneous consumers, while the storage capability is able to supplement the high power peak demands of the consumers and is also able to recover for future use most of the energy generated by the AAR systems during certain operating conditions.