US Patent 11415065 Material fatigue improvement for hybrid propulsion systems

Hybrid electric propulsion systems are described. The hybrid electric propulsion systems include a gas turbine engine including a low speed spool and a high speed spool, the low speed spool including a low pressure compressor and a low pressure turbine, and the high speed spool including a high pressure compressor and a high pressure turbine, a mechanical power transmission configured to at least one of extract power from and supply power to at least one of the low speed spool and the high speed spool, an electric motor configured to augment rotational power of at least one of the low speed spool and the high speed spool, and a controller operable to control a power augmentation of at least one of the low speed spool and the high speed spool during an operational stress state of operation of the gas turbine engine.