Control of low pressure generator for gas turbine engine

1. A system of turbofan gas turbine engines, each of the turbofan gas turbine engines comprises

a low pressure spool including a fan rotor, a low pressure turbine rotor, a low pressure drive shaft extending along an axis and rotationally coupling the fan rotor to receive driven rotation about the axis from the low pressure turbine rotor, and a low pressure motor-generator mounted on the low pressure drive shaft and adapted for selective operation between a generation mode to generate electric power from driven rotation of the low pressure turbine rotor and a drive mode to electrically drive rotation of the low pressure drive shaft, and

a high pressure spool including a compressor rotor, a high pressure turbine rotor, a high pressure drive shaft extending along the axis and rotationally coupling the compressor rotor to receive driven rotation about the axis from the high pressure turbine rotor, and a high pressure motor-generator adapted for selective operation between a generation mode to generate electric power from driven rotation of the high pressure turbine rotor and a drive mode to electrically drive rotation of the high pressure drive shaft,

wherein the system comprises a power control module including at least one processor for executing instructions stored on memory and an energy storage device electrically connected to the power control module to selectively communicate electric power with the power control module, the power control module electrically connected to each of the low pressure motor-generator and the high pressure motor-generator of the each of the turbofan gas turbine engines and configured to determine operational conditions of the each of the turbofan gas turbine engines and to selectively operate each of the low pressure motor-generators and the high pressure motor-generators in either of the generation mode and the drive mode based on the determined operational conditions of the corresponding turbofan gas turbine engine,

wherein the power control module is configured to selectively operate the low pressure motor-generator of a select one of the turbofan gas turbine engines in the drive mode to provide propulsion thrust assist in response to determination that the operational conditions include loss of engine power of the select one of the turbofan gas turbine engines,

wherein the power control module is configured to provide electrical power for operating the low pressure motor-generator of the select one of the turbofan gas turbine engines by operation of at least one of the low pressure motor-generator and the high pressure motor-generator of at least one other turbofan gas turbine engine in the generation mode,

wherein the power control module is configured to selectively store electric power from one of the low pressure motor-generator and the high pressure motor-generator in the energy storage device based on the determined operational conditions of the aircraft,

wherein the power control module is configured to determine that electric high bypass conditions exist in a select two turbofan gas turbine engines, the electric high bypass conditions comprising disengagement of the select two turbofan gas turbine engines,

wherein the power control module is configured to provide electrical power from the energy storage device for operating the low pressure motor-generator and the fan of each of the select two turbofan gas turbine engines in response to determination that the operational conditions include electric high bypass conditions, and

wherein each of the turbofan gas turbine engines is adapted for use in an aircraft, and the power control module is configured to operate the low pressure motor-generator in the generation mode and to operate the high pressure motor-generator in the drive mode to assist restart of the select one of turbofan gas turbine engines in response to determination that the operational conditions include in-flight restart.

2. The turbofan gas turbine engine of claim 1 , wherein the power control module is configured to operate the low pressure motor-generator in the generation mode in response to determination that the operational conditions are steady state operational conditions.

3. The turbofan gas turbine engine of claim 1 , wherein the power control module is configured to operate the low pressure motor-generator in the generation mode and to operate the high pressure motor-generator in the drive mode to assist rotation of the high pressure drive shaft in response to determination that the operational conditions include an efficiency of the high pressure spool that is below a predetermined threshold.

4. The turbofan gas turbine engine of claim 3 , wherein the predetermined threshold is a predetermined fuel efficiency of the high pressure spool.

5. The turbofan gas turbine engine of claim 3 , wherein the power control module is configured to operate the high pressure motor-generator in the generation mode and to operate the low pressure motor-generator in the drive mode to assist rotation of the low pressure drive shaft in response to determination that the operational conditions include an efficiency of the low pressure spool that is below a predetermined threshold.

6. The turbofan gas turbine engine of claim 1 , wherein the power control module is configured to operate the low pressure motor-generator in the generation mode and to operate the high pressure motor-generator in the drive mode to assist the rotation of the high pressure drive shaft in response to determination that the operational conditions are high demand operational conditions.

7. The turbofan gas turbine engine of claim 6 , wherein high demand operational conditions include determination that a compressor surge margin is below a predetermined threshold value.

8. The turbofan gas turbine engine of claim 6 , wherein the turbofan gas turbine engine is adapted for use in an aircraft and high demand operational conditions include determination that a flight altitude is above a predetermined threshold value.

9. The turbofan gas turbine engine of claim 6 , wherein high demand operational conditions include determination of a disruption of rotation of the fan rotor.