Hybrid amplification of high spool motoring via low spool power extraction and motoring of a differential geared generator
A power extraction and amplification system for a gas turbine engine is disclosed. In various embodiments, the power extraction and amplification system includes a low spool tower shaft configured for engagement with a low speed spool, a high spool tower shaft configured for engagement with a high speed spool, a first motor, a generator, a differential gear box operably coupled to the low spool tower shaft, to the first motor and to the generator, and a second motor operably coupled to the generator and the high spool tower shaft.
1. A power extraction and amplification system for a gas turbine engine, comprising:
a low spool tower shaft configured to engage a low speed spool;
a high spool tower shaft;
a first motor;
a generator;
a first coupling configured to couple the low speed spool to the first motor and to the generator, the first coupling including a differential and the low spool tower shaft; and
a second coupling configured to couple a high speed spool to a second motor and to the generator.
2. The power extraction and amplification system of claim 1 , wherein the second coupling configured to couple the high speed spool to the second motor and to the generator comprises the high spool tower shaft configured for engagement with the high speed spool.
3. The power extraction and amplification system of claim 2 , wherein the differential is a differential gear assembly configured to drive the generator.
4. The power extraction and amplification system of claim 3 , wherein the generator is configured to power the second motor.
5. The power extraction and amplification system of claim 4 , wherein the second motor is configured to drive the high spool tower shaft.
6. The power extraction and amplification system of claim 5 , wherein the first motor is operably coupled to the differential gear assembly via a first shaft and the generator is operably coupled to the differential gear assembly via a second shaft.
7. The power extraction and amplification system of claim 6 , wherein the generator is operably coupled to the second motor via an electric power cable.
8. The power extraction and amplification system of claim 7 , wherein the differential gear assembly includes a ring gear in meshing engagement with a bevel gear connected to the first shaft.
9. The power extraction and amplification system of claim 1 , wherein the first motor comprises one of a direct current motor and an alternating current motor and the second motor comprises one of a direct current motor and an alternating current motor.
10. A gas turbine engine, comprising:
a high speed spool rotationally connecting a high pressure compressor and a high pressure turbine;
a low speed spool rotationally connecting a low pressure compressor and a low pressure turbine;
a low spool tower shaft configured for engagement with the low speed spool;
a high spool tower shaft configured for engagement with the high speed spool;
a first motor;
a generator;
a differential gear assembly operably coupled to the low spool tower shaft, the first motor and the generator; and
a second motor operably coupled to the generator and the high spool tower shaft.
11. The gas turbine engine of claim 10 , wherein the low spool tower shaft is configured to provide a first power input to the differential gear assembly and the first motor is configured to provide a second power input to the differential gear assembly.
12. The gas turbine engine of claim 11 , wherein the differential gear assembly is configured to drive the generator and the generator is configured to power the second motor.
13. The gas turbine engine of claim 12 , wherein the second motor is configured to drive the high spool tower shaft.
14. The gas turbine engine of claim 13 , wherein the first motor comprises one of a direct current motor and an alternating current motor and the second motor comprises one of a direct current motor and an alternating current motor.
15. A gas turbine engine, comprising:
a high speed spool rotationally connecting a high pressure compressor and a high pressure turbine;
a low speed spool rotationally connecting a low pressure compressor and a low pressure turbine;
a first low spool tower shaft configured for engagement with the low speed spool;
a high spool tower shaft configured for engagement with the high speed spool;
a first differential gear assembly operably coupled to the first low spool tower shaft and to a first motor and to a first generator; and
a high spool tower shaft motor operably coupled to the high spool tower shaft and to the first generator.
16. The gas turbine engine of claim 15 , further comprising:
a second low spool tower shaft configured for engagement with the low speed spool; and
a second differential gear assembly operably coupled to the second low spool tower shaft and to a second motor and to a second generator, wherein the high spool tower shaft motor is operably coupled to the second generator.
17. The gas turbine engine of claim 16 , wherein the first generator provides a first power output to the high spool tower shaft motor at a first phase and the second generator provides a second power output to the high spool tower shaft motor at a second phase.
18. The gas turbine engine of claim 17 , wherein the high spool tower shaft motor is a brushless direct current motor.
19. The gas turbine engine of claim 18 , further comprising a controller configured to adjust a phase difference between the first phase and the second phase.