Differential geared turbine engine with torque modulation capability

• US 6,895,741 B2
• Filed: 06/23/2003
• Issued: 05/24/2005
• Est. Priority Date: 06/23/2003
• Status: Expired due to Fees

• Current Assignee: Pratt & Whitney Canada Corporation (Rtx Corporation)
• Original Assignee: Pratt & Whitney Canada Corporation (Rtx Corporation)
• Inventors: Harvey, Richard, Rago, Giuseppe
• Primary Examiner(s): Gartenberg, Ehud
• Application Number:
  US10/600,432
• Publication Number:
  US 20040255590A1
• Time in Patent Office: 701 Days
• Field of Search: 602/261, 607/72, 607/93, 607/92, 60/392.2
• US Class Current: 60/226.1
• CPC Class Codes: F01D 15/10 Adaptations for driving, or combinations with, electric generators
• CPC Class Codes: F01D 15/12 Combinations with mechanical gearing driven by multiple engines F01D13/00
• CPC Class Codes: F01D 25/36 using electric motors
• CPC Class Codes: F02C 7/32 Arrangement, mounting, or driving, of auxiliaries
• CPC Class Codes: F02C 7/36 Power transmission arrangements between the different shafts of the gas turbine plant, or between the gas-turbine plant and the power user F02C3/107 - F02C3/13 and F02C7/32 take precedence; couplings for transmitting rotation F16D; gearing in general F16H
• CPC Class Codes: F05D 2260/4031 as in toothed gearing
• CPC Class Codes: F05D 2260/40311 of the epicyclical, planetary or differential type
• CPC Class Codes: F05D 2270/053 Explicitly mentioned power
• CPC Class Codes: Y02T 50/60 Efficient propulsion technologies, e.g. for aircraft

Abstract

A method and apparatus for controllable distribution of power from a turbine of a gas turbine engine between two rotatable loads of the gas turbine engine, comprises transferring a shaft power of the turbine to the respective rotatable loads using differential gearing operatively coupled with the turbine and the rotatable loads, respectively; and controlling the power transfer using machines operatively coupled with the respective rotatable loads, operable as a generator or a motor for selectively taking power from one of the rotatable loads to drive the other of the rotatable loads, or the reverse.

Claims

1. A gas turbine engine comprising:

a compressor and a turbine in serial fluid communication;

a rotatable load;

a differential gearing system for receiving power from the turbine and transmitting power to the compressor and the rotatable load;

a first motor/generator mechanism coupled to the compressor for operating either as a motor to drive the compressor, or as a generator to take power from the compressor;

a second motor/generator mechanism coupled to the rotatable load for operating either as a motor to drive the rotatable load, or as a generator to take power from the rotatable load; and

the first and second motor/generator mechanisms being adapted for selectively modulating the torque versus speed characteristics of the compressor and the rotatable load, and for modulating the rotational speed relationship between the turbine, compressor and the rotatable load.

2. A gas turbine engine according to claim 1, wherein the differential gearing system comprises:

a first sun gear driven by the turbine at turbine rotational speed;

epicyclic gearing engaging the first sun gear and operatively connected to the compressor for rotationally driving the compressor at a first output rotational speed with respect to the turbine; and

an epicyclic carrier for operatively supporting the epicyclic gearing and being rotatable together with the epicyclic gearing, the epicyclic carrier being operatively connected to the rotatable load for driving the rotatable load in rotational motion at a second output rotational speed with respect to the turbine.

3. A gas turbine engine according to claim 2, wherein the epicyclic gearing comprises a plurality of first epicyclic gears engaging the first sun gear, and a plurality of second epicyclic gears co-axially coupled with the respective first epicyclic gears and operatively connected to the compressor.

4. A gas turbine engine according to claim 3, wherein the epicyclic gearing further comprises a second sun gear engaging the second epicyclic gears and being coupled with a compressor shaft for driving the compressor.

5. A gas turbine engine according to claim 2, wherein the epicyclic carrier comprises a cylindrical section co-axially coupled with a rotatable load shaft for driving the rotatable load.

6. A gas turbine engine according to claim 1, wherein the first and second motor/generator mechanisms comprise first and second permanent magnet motor/generators, respectively.

7. A gas turbine engine according to claim 6, wherein the first permanent motor/generator comprises a stator supported on a stationary structure of the engine and a rotor co-axially coupled with a compressor shaft, and the second permanent magnet motor/generator comprises a stator supported on a stationary structure of the engine and a rotor co-axially coupled with either a rotatable load shaft or a cylindrical section of the planet carrier.

8. A gas turbine engine according to claim 7, wherein the stator of each of the first and second permanent magnet motor/generators comprises a winding electrically connected to the controlling means.

9. A method for controllably distributing power from a turbine of a gas turbine engine between two rotatable loads of the gas turbine engine, comprising:

transferring a shaft power of the turbine to the respective rotatable loads using differential gearing operatively coupled with the turbine and the rotatable loads, respectively; and

controlling the power transfer using machines operatively coupled with the respective rotatable loads, operable as a generator or a motor for selectively taking power from one of the rotatable loads to drive the other of the rotatable loads, or the reverse.

10. A method according to claim 9, wherein the controlling step comprises:

operating the machine coupled with the compressor as a generator and the machine coupled with the rotatable load as a motor, to increase the rotation speed of the rotatable load.

11. A method according to claim 9, wherein the controlling step comprises:

operating the machine coupled with the compressor as a motor and the machine coupled with the rotatable load as a generator, to increase the rotation speed of the compressor.

12. A gas turbine engine comprising:

a compressor and a turbine in serial fluid communication;

a rotatable load;

a differential gearing system for receiving power from the turbine and transmitting power to the compressor and the rotatable load;

a first power means coupled to the compressor for one of driving the compressor and taking power from the compressor;

a second power means coupled to the rotatable load for one of driving the compressor and taking power from the rotatable load; and

the first and second power means being adapted for selectively modulating the torque versus speed characteristics of the compressor and the rotatable load, and for modulating the rotational speed relationship between the turbine, compressor and the rotatable load.