ARCHITECTURE FOR ELECTRIC MACHINE

• US 20080079401A1
• Filed: 11/16/2007
• Published: 04/03/2008
• Est. Priority Date: 05/27/2003
• Status: Active Grant

• Current Assignee: Pratt & Whitney Canada Corporation (Rtx Corporation)
• Original Assignee: Pratt & Whitney Canada Corporation (Rtx Corporation)
• Inventors: DOOLEY, KEVIN
• Granted Patent: US 7,583,063 B2
• Time in Patent Office: Days
• US Class Current: 322/90
• CPC Class Codes: H02K 1/2791 Surface mounted magnets; Inset magnets
• CPC Class Codes: H02K 16/04 Machines with one rotor and two stators
• CPC Class Codes: H02K 21/14 with magnets rotating within the armatures
• CPC Class Codes: H02K 21/22 with magnets rotating around the armatures, e.g. flywheel magnetos
• CPC Class Codes: H02K 3/12 arranged in slots
• CPC Class Codes: H02K 3/16 for auxiliary purposes, e.g. damping or commutating
• CPC Class Codes: H02K 3/28 Layout of windings or of connections between windings windings for pole-changing H02K17/06, H02K17/14, H02K19/12, H02K19/32
• CPC Class Codes: H02K 3/46 Fastening of windings on the stator or rotor structure
• CPC Class Codes: H02P 2101/30 for aircraft
• CPC Class Codes: H02P 9/02 Details of the control

Abstract

The invention includes an electric machine having a rotor, stator and at least one winding in the stator adapted to conduct a current, and a secondary winding, electrically isolated from the first winding and inductively coupled to the first winding, which may be used to control at least one of the output voltage and current of the first winding.

Claims

1. A method for operating a gas turbine engine, comprising the steps of:

providing the gas turbine engine, the engine having a main shaft drivingly connected to a multiple power output channel electric machine, the machine having a rotor and a stator, the stator having a plurality of non-overlapping sectors, each sector having a set of stator windings associated therewith, said sets of stator windings being electrically independent of one another, the stator sectors and associated windings each providing one of said multiple power output channels;

providing an electrical distribution system electrically connected to said power output channels of the machine, the channels connected to the electrical distribution system in parallel relative to one another;

operating the engine to rotate the rotor and thereby generate electricity;

in normal machine operation, combining the power output channels to provide a single power output to the electrical distribution system; and

in the event of a fault, shutting down at least one channel associated with said fault while continuing operation of a remainder of said channels to provide power output to the electrical distribution system.

2. The method as defined in claim 1, wherein in normal operation, the power output of each channel provides substantially equal current output to the electrical distribution system.

3. The method as defined in claim 1, wherein two channels are provided, the power output of each channel providing substantially half of a current output provided to the electrical distribution system.

4. The method as defined in claim 1, wherein the electrical distribution system comprises redundant engine accessory systems.

5. The method as defined in claim 1 further comprising providing electricity from the electrical distribution system to at least one of the group consisting of a plurality of power conditioning units, a plurality of engine pumps, and a plurality of electrically-run accessories.

6. The method as defined in claim 1, wherein each channel has primary windings and secondary windings, and wherein the method comprises the step of manipulating electricity in the secondary windings of said at least one channel associated with said fault to thereby reduce electrical output of the primary windings and thereby perform said shutdown of said channel.

7. The method as defined in claim 1, wherein three primary windings are provided in a 3-phase configuration in each said sector.

8. The method as defined in claim 1, wherein each channel is connected to the electrical distribution system via a corresponding primary circuit terminal.

9. An alternator comprising a rotor, a stator having at least one stator winding having a plurality of end turns exposed at an axial end of the stator, a fluid cooling jacket substantially surrounding the stator and the end turns, and an insert disposed intermediate the end turns and the cooling jacket, the cooling jacket communicating with a fluid coolant supply, the insert having jets for directing fluid coolant from the cooling jacket to the end turns, the insert comprised of at least one of copper and aluminium to thereby reduce stray inductance of the end turns.

10. The alternator as defined in claim 9, wherein the fluid coolant comprises oil.

11. The alternator as defined in claim 9, wherein the stator has primary and secondary windings, the end turns being part of the primary windings.

12. The alternator as defined in claim 11, wherein the alternator comprises passages inside the stator jacket to circulate the fluid coolant around and along the primary and secondary windings and thereby assist in cooling them.