DC excitation of the doubly fed brushless induction starter generator

Patent metadata

Field	Value
Publication number	US-10826366-B2
Application number	US-201916379004-A
Country	US
Kind code	B2
Filing date	Apr 9, 2019
Priority date	Apr 11, 2018
Publication date	Nov 3, 2020
Grant date	Nov 3, 2020

Abstract

A doubly fed brushless induction starter generator includes a stator and a rotor, which are separated by an air gap. The stator includes stator winding slots, each of which includes a first layer of power windings, a second layer of power windings, and a third layer of control windings, which include 2-pole single-phase windings. The control windings are arranged in the stator winding slots between the air gap and the first and second layers of power windings. Direct current is delivered to control windings in the generator as an excitation current to thereby produce a magnetic flux, through which the stator is moved to produce and alternating current in the power windings as an output current. The output current can be delivered to an electrical load, such as an electrical component on an aircraft.

First claim

The invention claimed is:

1. A brushless induction generator, comprising:
a rotor;
a stator including power windings, control windings, and winding slots, wherein each of the winding slots houses a first layer of power windings, a second layer of power windings, and a third layer of control windings, and wherein the first and second layers of the power windings are not directly coupled to the third layer of control windings; and
an air gap arranged between the rotor and the stator, wherein the third layer is arranged between the air gap and the first and second layers;
wherein the control windings are electrically connected to a power source,
wherein the power source provides direct current as an excitation current to the control windings, thereby producing a magnetic flux,
wherein the rotor moves through the magnetic flux, thereby generating an alternating current in the power windings as an output current,
wherein the power windings comprise 2-pole 3-phase windings and the control windings comprise 2-pole single-phase windings, and
wherein the control windings include two sets of concentric coils, and each of the concentric coils includes 15-25 turns of an electrically conductive wire.

2. The brushless induction generator according to claim 1 , wherein:
the first and second layers of power windings each occupy 10-25% of a depth of each of the winding slots; and
the third layer occupies 50-80% of the depth of each of the winding slots.

3. The brushless induction generator according to claim 1 , further including a controller that adjusts the excitation current in order to provide alternating current as the output current having a predetermined frequency at a given rotational speed of the rotor.

4. The brushless induction generator according to claim 1 , further comprising a rectifier that converts the output current from alternating current to direct current.

5. An aircraft, comprising:
a prime mover;
a power source;
an electrical load; and
a brushless induction generator mechanically connected to the prime mover, and electrically connected to the power source and the load, the brushless induction generator including:
a rotor,
a stator including winding slots, each of the winding slots housing a first layer of power windings, a second layer of power windings, and a third layer of control windings, and
an air gap arranged between the rotor and the stator,
wherein the power windings are not directly coupled to the control windings,
wherein the power source provides direct current as excitation current to the control windings, thereby producing a magnetic flux,
wherein the prime mover moves the rotor through the magnetic flux, thereby generating an alternating current in the power windings as an output current,
wherein the output current is delivered to the electrical load, and
wherein the third layer is arranged between the air gap and the first and second layers.

6. The aircraft according to claim 5 , wherein:
the control windings comprise 2-pole single-phase concentric coils; and
each of the concentric coils includes 15-25 turns of a wire.

7. The aircraft according to claim 5 , wherein:
the first and second layers each occupy 10-25% of a depth of each of the winding slots; and
the third layer occupies 50-80% of the depth of each of the winding slots.

8. The aircraft according to claim 5 , further including a controller that adjusts the excitation current thereby providing alternating current as the output current having a predetermined frequency at a given rotational speed of the rotor.

9. The aircraft according to claim 5 , further including a rectifier that converts the output current from alternating current to direct current.

10. The aircraft according to claim 5 , wherein the prime mover comprises an engine of the aircraft.

11. The aircraft according to claim 5 , wherein the electrical load is an electrical component of the aircraft.

12. A method of generating electrical power, comprising:
providing a brushless induction generator that includes a rotor, a stator including winding slots, power windings and control windings, and an air gap arranged between the rotor and the stator;
supplying a direct current to the control windings as an excitation current to thereby produce a magnetic flux; and
moving the rotor through the magnetic flux, thereby producing an alternating current in the power windings as an output current, wherein the first and second layers each occupy 10-25% of a depth of each of the winding slots and a third layer occupies 50-80% of the depth of each of the winding slots.

13. The method according to claim 12 , wherein:
the power windings comprise 2-pole 3-phase windings; and
the control windings comprise 2-pole single-phase windings.

14. The method according to claim 12 , wherein:
each of the winding slots houses a first layer of power windings, a second layer of power windings, and a third layer of control windings;
the first and second layers of power windings are not directly coupled to third layer of control windings; and
the third layer is arranged between the air gap and the first and second layers.

15. The method according to claim 12 , further comprising:
adjusting the excitation current in order to provide alternating current as the output current having a predetermined frequency at a given rotational speed of the rotor; and
converting the output current from alternating current to direct current.

16. The method according to claim 12 , further comprising:
providing an aircraft that includes the brushless induction generator, a power source, and a prime mover;
mechanically connecting the prime mover to the rotor, wherein the prime mover moves the rotor through the magnetic flux;
electrically connecting the power source to the control windings, wherein the power source supplies the excitation current to the control windings.

17. The method according to claim 12 , wherein:
the control windings comprise 2-pole single-phase concentric coils; and
each of the concentric coils includes 15-25 turns of a wire.

Assignees

• Safran Electrical & Power

Inventors

• Bailey Mark Wesley

Classifications

• H02K19/26

  characterised by the arrangement of exciting windings · CPC title

• H02K17/42 Primary

  Asynchronous induction generators (H02K17/02 takes precedence) · CPC title

• H02K3/48

  in slots · CPC title

• H02K3/18

  Windings for salient poles · CPC title

• H02K1/14

  Stator cores with salient poles · CPC title