Hybrid-electric propulsion system for an aircraft

Patent metadata

Field	Value
Publication number	US-11230385-B2
Application number	US-201715617080-A
Country	US
Kind code	B2
Filing date	Jun 8, 2017
Priority date	Jun 8, 2017
Publication date	Jan 25, 2022
Grant date	Jan 25, 2022

Abstract

A hybrid-electric propulsion system for an aircraft includes a turbomachine, the turbomachine including a first spool and a second spool. A method for operating the hybrid electric propulsion system includes operating, by one or more computing devices, the turbomachine such that the first spool mechanically drives a prime propulsor of the hybrid-electric propulsion system; and modifying, by the one or more computing devices, a speed relationship parameter defined between the first spool and second spool by providing electrical power to, or drawing electrical power from, an electric machine mechanically coupled to the first spool, the second spool, or both.

First claim

What is claimed is:

1. A method of operating a hybrid-electric propulsion system for an aircraft having a turbomachine, the turbomachine including a first spool and a second spool, the method comprising:
operating, by one or more computing devices, the turbomachine such that the first spool mechanically drives a prime propulsor of the hybrid-electric propulsion system, the turbomachine comprising a low pressure compressor and a high pressure compressor in a serial flow relationship from the low pressure compressor to the high pressure compressor; and
modifying, by the one or more computing devices, a speed relationship parameter defined between the first spool and the second spool by providing electrical power to the second spool via an electric machine when the first spool reduces speed at a first rate and the second spool reduces speed at a second rate that is faster than the first rate during a thrust reduction operation, wherein the first spool is a low pressure spool, wherein the second spool is a high pressure spool, and wherein the electric machine is coaxially coupled to the first spool forward of the low pressure compressor of the turbomachine.

2. The method of claim 1 , wherein modifying, by the one or more computing devices, the speed relationship parameter defined between the first spool and the second spool comprises:
receiving, by the one or more computing devices, data indicative of a rotational speed of the first spool;
receiving, by the one or more computing devices, data indicative of a rotational speed of the second spool; and
determining, by the one or more computing devices, the speed relationship parameter is outside a desired speed relationship parameter range.

3. The method of claim 1 , further comprising:
modifying, by the one or more computing devices, a fuel flow to a combustion section of the turbomachine;
wherein modifying, by the one or more computing devices, the speed relationship parameter defined between the first spool and the second spool comprises providing, by the one or more computing devices, electrical power to, or drawing, by the one or more computing devices, electrical power from, the electric machine to bring or maintain the speed relationship parameter within a desired speed relationship parameter range.

4. The method of claim 3 , wherein modifying, by the one or more computing devices, the fuel flow to the combustion section of the turbomachine comprises reducing, by the one or more computing devices, the fuel flow to the combustion section of the turbomachine such that a speed of the second spool is urged to reduce relative to a speed of the first spool.

5. The method of claim 4 , wherein modifying, by the one or more computing devices, the speed relationship parameter defined between the first spool and the second spool comprises drawing, by the one or more computing devices, electrical power from the electric machine to bring or maintain the speed relationship parameter within the desired speed relationship parameter range.

6. The method of claim 5 , wherein reducing, by the one or more computing devices, the fuel flow to the combustion section of the turbomachine comprises initiating, by the one or more computing devices, a flight phase of the aircraft involving a reduction in power demand from the turbomachine.

7. The method of claim 3 , wherein modifying, by the one or more computing devices, the fuel flow to the combustion section of the turbomachine comprises increasing, by the one or more computing devices, the fuel flow to the combustion section of the turbomachine such that a speed of the second spool is urged to increase relative to a speed of the first spool.

8. The method of claim 7 , wherein modifying, by the one or more computing devices, the speed relationship parameter defined between the first spool and the second spool comprises providing, by the one or more computing devices, electrical power to the electric machine to bring or maintain the speed relationship parameter within the desired speed relationship parameter range.

9. The method of claim 3 , wherein modifying, by the one or more computing devices, the speed relationship parameter defined between the first spool and the second spool comprises wherein modifying, by the one or more computing devices, the speed relationship parameter while providing substantially all of an airflow from the low pressure compressor to the high pressure compressor.

10. The method of claim 1 , wherein the speed relationship parameter is an acceleration mismatch between the first spool and the second spool.

11. The method of claim 1 , wherein the hybrid electric propulsion system further comprises an electric energy storage unit, wherein the electric energy storage unit is electrically connectable to the electric machine, and wherein modifying, by the one or more computing devices, the speed relationship parameter between the first spool and the second spool comprises modifying, by the one or more computing devices, the speed relationship parameter by providing electrical power to the electric machine from the electric energy storage unit, or drawing electrical power from the electric machine to the electric energy storage unit.

12. The method of claim 11 , wherein the electric energy storage unit is configured to store between about fifty kilowatt hours and five hundred kilowatt hours of electrical power.

13. A hybrid-electric propulsion system for an aircraft comprising:
a turbomachine comprising a first spool operably coupled with a low pressure compressor, a second spool operably coupled with a high pressure compressor in a serial flow arrangement and downstream of the low pressure compressor in an axial direction, and a combustion section, wherein the first spool reduces speed at a first rate and the second spool reduces speed at a second rate that is faster than the first rate during a thrust reduction operation;
a prime propulsor mechanically coupled to the first spool such that the first spool rotates the prime propulsor during operation;
an electric machine mechanically coupled to the first spool forward of the low pressure compressor;
an electric energy storage unit electrically connectable to the electric machine; and
a controller comprising memory and one or more processors, the memory storing instructions that when executed by the one or more processors cause the hybrid-electric propulsion system to perform functions, the functions including:
modifying a speed relationship parameter between the first spool and the second spool by providing electrical power to the electric machine mechanically coupled to the second spool to reduce the second rate of the second spool.

14. The hybrid-electric propulsion system of claim 13 , wherein the turbomachine comprises a duct extending from the low pressure compressor to the high pressure compressor, wherein the duct is fixed in position during all operating conditions of the turbomachine.

15. The hybrid-electric propulsion system of claim 13 , wherein the turbomachine comprises a duct extending from the low pressure compressor to the high pressure compressor, wherein the duct does not define any bleed valve openings.

16. The hybrid-electric propulsion system of claim 13 , wherein the instructions further include:
modifying a fuel flow to the combustion section of the turbomachine;
wherein modifying the speed relationship parameter defined between the first spool and the second spool comprises providing electrical power to, or drawing electrical power from, the electric machine to bring or maintain the speed relationship parameter within a desire

Assignees

• Gen Electric

Inventors

• Adibhatla Sridhar
• Hon Robert Charles
• Gansler Michael Thomas

Classifications

• B64D35/024

  of series type · CPC title

• B64D35/025

  of parallel type · CPC title

• B64D31/06

  actuated automatically · CPC title

• B64D27/35

  Arrangements for on-board electric energy production, distribution, recovery or storage · CPC title

• B64D35/023

  of series-parallel type · CPC title