EP-4737702-A2 - HYBRID-ELECTRIC PROPULSION SYSTEM EQUIPPED WITH A COUPLER FOR SWITCHING BETWEEN MODES OF OPERATION

Abstract

A propulsion assembly includes a first torque source coupled with a first shaft and a second torque source coupled with a second shaft. A coupler selectively couples the first and second torque sources. When the first and second torque sources are coupled via the coupler, in response to a command to decouple the first torque source, an unloading operation is performed to decrease the torque output provided by the first torque source to a threshold, and when reached, the first shaft is decoupled from the coupler. When the first torque source is coupled with the coupler but the second torque source is not, in response to a command to couple the second torque source, a speed matching operation is performed to increase the speed of the second shaft to match a speed of the first shaft, and when the speeds are matched, the second shaft is coupled to the coupler.

Inventors

• ZATORSKI, DAREK TOMASZ
• MURROW, KURT DAVID
• GEMIN, PAUL ROBERT
• CIOFFI, Philip
• YAGIELSKI, JOHN RUSSELL

Assignees

• General Electric Company

Dates

Publication Date

20260506

Application Date

20230705

Claims (15)

1. A method, comprising: providing, by an electric machine, a motor torque output on a coupler mechanically coupled with a propulsor to drive the propulsor; performing, in response to a power turbine couple command, a speed matching operation, wherein performing the speed matching operation comprises increasing a rotational speed of a power turbine shaft mechanically coupled with a power turbine until the rotational speed of the power turbine shaft matches or is within a predetermined range of a rotational speed of an electric machine shaft that mechanically couples the electric machine to the coupler; and when the rotational speed of the power turbine shaft matches or is within the predetermined range of the rotational speed of the electric machine shaft, mechanically coupling the power turbine to the coupler so that the power turbine drives the propulsor.
2. The method of claim 1, wherein after the power turbine is mechanically coupled to the coupler, a torque output provided by the power turbine on the coupler is held constant or substantially constant for a predetermined time.
3. The method of any one of the preceding claims, wherein after the power turbine is mechanically coupled to the coupler, the method further comprises: decreasing the motor torque output provided by the electric machine on the coupler to decrease mechanical power transmission from the electric machine to the propulsor; and increasing the torque output provided by the power turbine on the coupler to increase mechanical power transmission from the power turbine to the propulsor.
4. The method of claim 3, wherein: the motor torque output provided by the electric machine on the coupler is decreased linearly; and/or the torque output provided by the power turbine on the coupler is increased linearly.
5. The method of any one of the preceding claims, wherein the motor torque output provided by the electric machine on the coupler is decreased and a torque output provided by the power turbine on the coupler is increased so that a net torque provided by the electric machine and the power turbine on the coupler is maintained within a predetermined margin of a commanded torque.
6. The method of any one of the preceding claims, wherein the motor torque output provided by the electric machine on the coupler is decreased and a torque output provided by the power turbine on the coupler is increased so that a net torque provided by the electric machine and the power turbine on the coupler is maintained at or substantially at a constant torque over a turbine loading period.
7. The method of any one of the preceding claims, wherein the motor torque output provided by the electric machine on the coupler is decreased at a rate and a torque output provided by the power turbine on the coupler is increased at or substantially at the rate.
8. The method of any one of the preceding claims, wherein the motor torque output provided by the electric machine on the coupler is decreased so that the electric machine switches from a motoring mode to a generating mode to generate electrical power.
9. The method of any one of the preceding claims, wherein the motor torque output provided by the electric machine on the coupler is decreased so that the electric machine provides a generator torque output on the coupler.
10. The method of any one of the preceding claims, wherein the motor torque output provided by the electric machine on the coupler is decreased so that the electric machine ceases providing the motor torque output on the coupler, and when the electric machine ceases providing the motor torque output on the coupler, the method further comprises: mechanically decoupling the electric machine from the coupler, wherein mechanically decoupling the electric machine from the coupler optionally comprises modulating one or more actuators to move a coupler electric machine shaft of the coupler so that torque transmitting features of the coupler electric machine shaft disengage from torque transmitting features of the electric machine shaft.
11. The method of any one of the preceding claims, wherein mechanically coupling the power turbine to the coupler comprises modulating one or more actuators to move a coupler turbine shaft of the coupler so that torque transmitting features of the coupler turbine shaft engage torque transmitting features of the power turbine shaft.
12. The method of any one of the preceding claims, further comprising: monitoring whether the rotational speed of the power turbine shaft matches or is within the predetermined range of the rotational speed of the electric machine shaft based at least in part on one or more inputs received from a resolver associated with the electric machine shaft and one or more inputs received from a resolver associated with the power turbine shaft.
13. A controller, comprising: one or more memory devices; one or more processors configured to: cause an electric machine to provide a motor torque output on a coupler mechanically coupled with a propulsor to drive the propulsor; in response to a power turbine couple command, cause a speed matching operation to be performed, wherein performing the speed matching operation comprises increasing a rotational speed of a power turbine shaft mechanically coupled with a power turbine until the rotational speed of the power turbine shaft matches or is within a predetermined range of a rotational speed of an electric machine shaft that mechanically couples the electric machine to the coupler; and when the rotational speed of the power turbine shaft matches or is within the predetermined range of the rotational speed of the electric machine shaft, cause the power turbine to become mechanically coupled with the coupler so that the power turbine drives the propulsor.
14. A propulsion assembly, comprising: a gas turbine engine that includes a power spool having a power turbine and a power turbine shaft mechanically coupled with the power turbine; a propulsor assembly that includes a propulsor shaft mechanically coupled with a propulsor; an electric machine; a coupler; and the controller of claim 13.
15. A non-transitory computer readable medium comprising computer-executable instructions, which, when executed by one or more processors of a computing system of an aircraft, cause the one or more processors to: cause an electric machine to provide a motor torque output on a coupler mechanically coupled with a propulsor to drive the propulsor; in response to a power turbine couple command, cause a speed matching operation to be performed, wherein performing the speed matching operation comprises increasing a rotational speed of the power turbine shaft until the rotational speed of the power turbine shaft matches or is within a predetermined range of a rotational speed of an electric machine shaft that mechanically couples the electric machine to the coupler; and when the rotational speed of the power turbine shaft matches or is within the predetermined range of the rotational speed of the electric machine shaft, cause the power turbine to become mechanically coupled with the coupler so that the power turbine drives the propulsor.

Description

FIELD The present disclosure relates to hybrid-electric propulsion systems for aircraft. BACKGROUND Hybrid-electric propulsion systems are being developed to improve an efficiency of aircraft. Such propulsion systems can include a gas turbine engine, an electric machine, and a propulsor, such as a fan or propeller. The integration of an electric machine with a gas turbine engine may present certain operational challenges in balancing or shifting the power between the electric machine and the gas turbine engine, maximizing the efficiency of the entire propulsion system, and/or coupling/decoupling these components from one another for safety or other operational purposes. Accordingly, a system designed to address one or more of these challenges would be a welcome addition to the art. BRIEF DESCRIPTION OF THE DRAWINGS A full and enabling disclosure of the present disclosure, including the best mode thereof, directed to one of ordinary skill in the art, is set forth in the specification, which makes reference to the appended figures, in which: FIG. 1 is a schematic top view of an exemplary aircraft having a hybrid-electric propulsion system in accordance with an exemplary aspect of the present disclosure;FIG. 2 is a schematic cross-sectional view of a propulsion assembly of the aircraft of FIG. 1;FIG. 3 is a cross-sectional view of a coupler of the propulsion assembly of FIG. 2;FIG. 4 is a schematic view of the coupler of FIG. 3 and depicts a first mode of operation in which a propulsor shaft, a power turbine shaft, and an electric machine shaft are all mechanically coupled with the coupler;FIG. 5 is a schematic view of the coupler of FIG. 3 and depicts a second mode of operation in which the propulsor shaft and the power turbine shaft are mechanically coupled with the coupler while the electric machine shaft is mechanically decoupled from the coupler;FIG. 6 is a schematic view of the coupler of FIG. 3 and depicts a third mode of operation in which the propulsor shaft and the electric machine shaft are mechanically coupled with the coupler while the power turbine shaft is mechanically decoupled from the coupler;FIG. 7 is a schematic view of the coupler of FIG. 3 and depicts a fourth mode of operation in which the power turbine shaft is mechanically coupled with the coupler while the propulsor shaft and the electric machine shaft are mechanically decoupled from the coupler;FIG. 8 is a schematic view of the coupler of FIG. 3 and depicts a fifth mode of operation in which the power turbine shaft and the electric machine shaft are mechanically coupled with the coupler while the propulsor shaft is mechanically decoupled from the coupler;FIG. 9 is a schematic view of the coupler of FIG. 3 and depicts a sixth mode of operation in which the power turbine shaft, the propulsor shaft, and the electric machine shaft are mechanically decoupled from the coupler;FIG. 10 is a data flow diagram depicting an example manner in which the coupler of FIG. 3 can be controlled to couple/decouple various components to or from the coupler;FIG. 11 a flow diagram of a method of decoupling a turbine from a coupler in accordance with an exemplary aspect of the present disclosure;FIG. 12 is a graph corresponding to the method of decoupling the turbine from the coupler set forth in FIG. 11 and depicts a speed of the power turbine and a speed of the electric machine as functions of time and a torque output of the power turbine and a torque output of the electric machine as functions of time;FIG. 13 a flow diagram of a method of coupling a turbine to a coupler in accordance with an exemplary aspect of the present disclosure;FIG. 14 is a graph corresponding to the method of coupling the turbine to the coupler set forth in FIG. 13 and depicts a speed of the power turbine and a speed of the electric machine as functions of time and a torque output of the power turbine and a torque output of the electric machine as functions of time;FIG. 15 a flow diagram of a method of decoupling an electric machine from a coupler in accordance with an exemplary aspect of the present disclosure;FIG. 16 is a graph corresponding to the method of decoupling the electric machine from the coupler set forth in FIG. 15 and depicts a speed of the power turbine and a speed of the electric machine as functions of time and a torque output of the power turbine and a torque output of the electric machine as functions of time;FIG. 17 a flow diagram of a method of coupling an electric machine to a coupler in accordance with an exemplary aspect of the present disclosure;FIG. 18 is a graph corresponding to the method of coupling the electric machine to the coupler set forth in FIG. 17 and depicts a speed of the power turbine and a speed of the electric machine as functions of time and a torque output of the power turbine and a torque output of the electric machine as functions of time;FIG. 19 is a schematic cross-sectional view of a propulsion assembly for an aircraft in accordanc