Rolls-royce Corporation

David F Brookes

Graham P Bruce

Stephen Mark Husband

Martin Kenneth Yates

Mark Sweet

Jeffrey Hobday

Luke Ashton

An electrical system having a first dual-wound rotary electric machine mechanically coupled with a first gas turbine spool and having a first three-phase sub-machine and a second three-phase submachine; a second dual-wound rotary electric machine mechanically coupled with a second gas turbine spool and having a third three-phase sub-machine and a fourth three-phase submachine; and a set of N=4 bidirectional converter circuits for conversion of alternating current (ac) to and from direct current (dc), each of which has an associated index n=(1, . . . , N), and for all n, the ac side of the nth bidirectional converter circuit is connected with the nth three-phase sub-machine. The dc side of the first converter circuit is connected with the dc side of the third converter circuit, and the dc side of the second converter circuit is connected with the dc side of the fourth converter circuit.

Electrical systems with dual-wound rotary electric machines

A stator for a radial-flux rotary electric machine includes a yoke with a plurality of teeth, each tooth extending from a root at the yoke to a tip. The stator further includes a plurality of coils, each one of which being located on a respective one of the plurality of teeth, the coils being sized such that a slot fill factor is between zero and unity to define axial voids in the slots. The stator further includes a plurality of magnetic sealing members, each one of which being engaged with the tips of adjacent teeth to circumferentially and axially seal the axial voids in the slots for retaining an axial flow of coolant therein, the magnetic sealing members being composed of a magnetic material to provide a flux path between adjacent tooth tips to increase an amount of leakage flux.

Electric machines

Electrical systems for connecting rotary electric machines with gas turbine spools are provided. One such electrical system includes: a first rotary electric machine; a second rotary electric machine; a first set of bidirectional converter circuits; a second set of bidirectional converter circuits; and DC outputs for connection with an R-channel network. Each electrical machine is mechanically coupled with a respective gas turbine spool and has an identical even number N&#x2265;4 of phases, each phase having a respective index and including an identical number P&#x2265;1 of coils wound in a P-plex configuration in which adjacent phases are radially separated by 2&#x3c0;/NP mechanical radians. Each of the first and second converter circuits converts AC to and from DC, has a respective index n, and is connected with the P coils in the nth phase of the first and second rotary electric machines, respectively.

Electrical systems

Electrical systems for connecting rotary electric machines with gas turbine spools are provided. One such electrical system comprises: a first rotary electric machine mechanically coupled with a first gas turbine spool and a second rotary electric machine mechanically coupled with a second gas turbine spool, each said electric machine having an identical even number N&#x2265;4 of phases, each phase having a respective index n=(1, . . . , N), and each phase comprising an identical number P&#x2265;1 of coils wound in a P-plex configuration in which adjacent phases are radially separated by 2&#x3c0;/NP mechanical radians; a first set of N bidirectional converter circuits for conversion of alternating current (ac) to and from direct current (dc), each converter circuit having a respective index n and being connected with the P coils in the nth phase of the first rotary electric machine; and a second set of N bidirectional converter circuits for conversion of ac to and from dc, each converter circuit having a respective index n and being connected with the P coils in the nth phase of the second rotary electric machine. For all n, a dc side of the nth converter circuit in said first set is connected with a dc side of the nth converter circuit in said second set to facilitate dc power transfer between the first gas turbine spool and the second gas turbine spool.

Electrical system having two rotary electric machines coupled to two gas turbine spools

Gas turbine engines and methods of starting gas turbine engines, the gas turbine engine including: an electronic engine controller; one or more spools designated a starting spool for starting the engine, and has a required starting torque &#x3c4;s; a permanent magnet alternator mechanically coupled with the starting spool, the alternator, in a motor mode, provides a peak torque of &#x3c4;a, and, in a generator mode, generates electrical power for the electronic engine controller; and an electrical starter-generator mechanically coupled with the starting spool. The starter-generator in a motor mode, provides a peak torque of &#x3c4;sg, and, in a generator mode, generates electrical power for an external load. &#x3c4;sg+&#x3c4;a&#x2265;&#x3c4;s and &#x3c4;sg, &#x3c4;a&#x3c;&#x3c4;s, and the electronic engine controller, during a start procedure, operates both the permanent magnet alternator and the starter-generator in a motor mode to drive the starting spool.

Gas turbine engine

A power electronics unit for an aircraft and a method of determining the integrity of a power electronics unit are provided. The power electronics unit comprises an electric machine controller; a heatsink arranged to conduct heat from the electric machine controller; a housing comprising a sealed internal volume enclosing the electric machine controller and heatsink; a dielectric liquid partially filling the internal volume to cover the electric machine controller; a gas pocket within the internal volume; a pressure sensor arranged to measure a pressure of gas within the gas pocket; a temperature sensor arranged to measure a temperature within the internal volume; and a controller. The controller is configured to receive signals from the pressure sensor and temperature sensor, determine a pressure and temperature from the received signals and provide an output signal dependent on the determined temperature and pressure.

Power electronics unit

A multi-logic device system, an electronic engine controller, and a method of operating the multi-logic device system. The multi-logic device system includes a primary logic device which is more resilient to single event effects, and one or more secondary logic devices, each secondary logic device being powered by a respective power supply unit and being more susceptible to single event effects. The primary logic device is configured to run, for each secondary logic device, a respective watchdog timer. Each watchdog timer is restarted upon receipt of a restart signal from the respective secondary logic device. The primary logic device is also configured, in response to a watchdog timer timing out, to identify and reset the secondary logic device corresponding to the timed out watchdog timer.

Single event effect mitigation

A turboelectric generator system includes a gas turbine engine which includes, in fluid flow series, a gas-generator compressor, a combustor, a gas-generator turbine, and a variable-speed free power turbine. The system further comprises a variable-frequency electric machine rotatably connected with the free power turbine and a power converter configured to convert a variable frequency electrical output from the electric machine to a fixed frequency output.

Turboelectric generator system

A rotor for an electrical machine is provided. The rotor comprises: a rotor body; one or more magnets arranged around the rotor body; and a non-magnetic containment sleeve positioned radially outwardly of the one or more magnets. The containment sleeve has axially-alternating solid ring sections and reticulated ring sections.

Electrical machine rotor

An axial piston pump has a fluid inlet, a fluid outlet, and a rotatable, one-piece piston housing carrying one or more pistons movable within one or more respective sleeves formed by the housing. A circumferential row of fixed field members is mounted to the housing at a mounting location formed by the housing, the mounting location being radially outward of the sleeve(s). The pump further has a stator surrounding the piston housing and including a circumferential row of armature windings such that the piston housing and the stator form an electro-magnetic motor operable to rotate the piston housing, and a swashplate engaged with the piston(s) such that rotation of the piston housing relative to the swashplate around an axis of rotation produces reciprocating movement of the piston(s) for the pressurisation of fluid received into the sleeve(s) from the fluid inlet and then discharged from the sleeve(s) to the fluid outlet.

Axial piston pump having a piston housing having fixed field members mounted thereto and interacting with a stator surrounding the housing and configured to generate a force which urges the housing in an axial direction

An aero-engine low pressure pump is provided for supplying fuel at a raised pressure to a high pressure pump. The low pressure pump has a pumping mechanism which raises the pressure of fuel flowing though the mechanism. The low pressure pump further has electrical motor which drives the pumping mechanism. The low pressure pump further has a variable frequency motor drive which supplies electrical power to the electrical motor. The variable frequency motor drive measures the electrical power supplied to the electrical motor. The low pressure pump further has a control unit which compares the measured electrical power to a reference power, and, when the measured electrical power is less than the reference power by a predetermined amount, controls the motor drive to increase the power supplied to the electrical motor thereby increasing the pressure rise produced by the pumping mechanism.

Aero-engine low pressure pump

A gear pump has first and second meshing gears for pumping a fluid. The gear pump further has a first electrical motor having a first rotor, a first stator and first coil windings. The gear pump further has a second electrical motor having a second rotor, a second stator and second coil windings. The first rotor is operatively connected to the first gear and the second rotor is operatively connected to the second gear such that each gear is rotated by its respective rotor. The first and second coil windings are energized by respective and separate first and second electrical power circuits such that the first and second meshing gears can be driven independently of each other.

Gear pump

A combination of a gas turbine pressure sensing assembly and an engine electronics unit. The pressure sensing assembly includes a pressure manifold having an air inlet and one or more air outlets. The pressure sensing assembly further includes one or more pressure sensors connected to the air outlets to sense the pressure of air entering through the air inlet. The engine electronics unit in operation produces waste heat. The pressure sensing assembly further includes a heat conduction path which thermally connects the engine electronics unit to the manifold such that the manifold acts as a sink for the waste heat. The temperature rise of the manifold produced by the waste heat preventing icing of the manifold.

Icing prevention of a gas turbine engine pressure sensing assembly

A surface mountable, toroid magnetic device is provided, the device having a potting filling the central hole of the toroid. The potting extends axially beyond the base of the toroid to form a contact surface which, in use, contacts a mounting body for the device. Heat generated by the device flows by conduction through walls of the toroid defining the central hole into the potting and then through the contact surface into the mounting body.

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Derby, United Kingdom

David F Brookes