Power transfer assembly for an aircraft propulsion system

A method for operating an aircraft propulsion system, the method comprising:

• rotating a high-pressure (HP) spool and a low-pressure (LP) spool of a gas turbine engine;
• operating a motor control assembly of a power transfer assembly between the HP spool and the LP spool in a first state or a second state, in the first state operating a first motor-generator coupled with the HP spool to apply a first rotational force to the HP spool and operating a second motor-generator coupled with the LP spool to supply electrical power to the first motor-generator, and in the second state operating the second motor-generator to apply a second rotational force to the LP spool and operating the first motor-generator to supply electrical power to the second motor-generator;
• and
• in the first state and the second state, controlling the motor control assembly at a controller connected in signal communication with the motor control assembly to control an operating voltage of the power transfer assembly at the first motor-generator and the second motor-generator at a target operating voltage selected at the controller in response to an aircraft altitude input to the controller.

An aircraft propulsion system comprising:

• a power transfer assembly including a motor-generator assembly and a motor control assembly, the motor-generator assembly including a first motor-generator and a second motor-generator, the motor control assembly electrically connected to the first motor-generator and the second motor-generator, the motor control assembly configured to control an operating voltage of the power transfer assembly at the first motor-generator and the second motor-generator;
• and
• a controller connected in signal communication with the motor control assembly, the controller including a processor connected in signal communication with a non-transitory memory storing instructions which, when executed by the processor, cause the processor to:
• identify a target operating voltage of the power transfer assembly selected in response to an aircraft altitude input to the controller, and the target operating voltage and the aircraft altitude input have an inverse relationship;
• and
• control the motor control assembly to control the operating voltage at the target operating voltage.