Method for powering autonomous drive motors for an aircraft

1. A method for powering an autonomous drive device ( 4 ) in an aircraft comprising a plurality of drive motors ( 5 ) for selectively driving wheels ( 6 ) at least when jet engines of the aircraft are not activated, the aircraft comprising an auxiliary power unit (APU) ( 2 ) driving a first generator ( 1 ) for supplying electric power to electrical devices on the aircraft that need to be powered when the jet engines are not activated, the method comprising:

using a second generator ( 8 ) exclusively dedicated to the electric power supply of the autonomous drive device,

using a gearbox coupled to the APU and to the first and second generators so that the first and second generators are disposed in parallel, the gearbox being adapted to transmit mechanical power from the APU to the first and second generators so that the first and second generators can be driven in parallel by the APU, and

using the gearbox to transmit mechanical power from the second generator to the first generator when the second generator operates as a motor under the action of power recovered by the autonomous drive device, so as to assist the APU to drive at least the first generator.

2. The method according to claim 1 , comprising controlling the speed of the aircraft over the ground by:

powering the autonomous drive motors in order to accelerate the aircraft up to a requested speed if an actual speed of the aircraft is lower than the said requested speed, and

conversely, operating the motors as generators in order to slow down the aircraft until the requested speed is reached if the actual speed of the aircraft is higher than the requested speed,

wherein power recovered by the motors is fed back to the second generator.

3. A power generation assembly for an aircraft comprising:

an auxiliary power unit (APU) ( 2 ) capable of delivering a mechanical power;

a main gearbox ( 9 ) driven by a drive shaft coming from the APU;

an autonomous drive device ( 4 ) comprising a plurality of drive electric motors ( 5 ) for selectively driving wheels ( 6 ) of the aircraft;

at least first and second generators ( 1 , 8 );

wherein said first generator ( 1 ) supplies electric power to devices on the aircraft that need to be powered when jet engines of the aircraft are not activated;

wherein said second generator ( 8 ) is exclusively dedicated to supplying electric power to the autonomous drive device so as to drive the electric motors ( 5 ) for selectively driving wheels ( 6 ) of the aircraft;

wherein said first and second generators ( 1 , 8 ) are mechanically coupled to the main gearbox,

wherein the main gearbox is adapted to transmit mechanical power from the APU to the first and second generators so that the first and second generators can be driven in parallel by the APU; and

wherein the main gearbox is further configured, when the second generator operates as a motor, for transmitting a transmission of mechanical power from the second generator to at least the first generator, so as to assist the APU to drive at least the first generator.

4. A method for powering an autonomous drive device ( 4 ) in an aircraft comprising a plurality of drive motors ( 5 ) for selectively driving wheels ( 6 ) at least when jet engines of the aircraft are not activated, the aircraft comprising an auxiliary power unit (APU) ( 2 ) driving a first generator ( 1 ) for supplying electric power to electrical devices on the aircraft that need to be powered when the jet engines are not activated, the method comprising:

using a second generator ( 8 ) dedicated to the electric power supply of the autonomous drive device,

using a gearbox mechanically coupled to the APU and to the first and second generators so that the first and second generators are disposed in parallel, the gearbox being adapted to transmit mechanical power from the APU to the first and second generators so that the first and second generators can be driven in parallel by the APU, and

using the gearbox to transmit mechanical power from the second generator to the first generator when the second generator operates as a motor under the action of power recovered by the autonomous drive device, so as to assist the APU to drive at least the first generator.