US Patent 11230385 Hybrid-electric propulsion system for an aircraft

A hybrid-electric propulsion system for an aircraft includes a turbomachine, the turbomachine including a first spool and a second spool. A method for operating the hybrid electric propulsion system includes operating, by one or more computing devices, the turbomachine such that the first spool mechanically drives a prime propulsor of the hybrid-electric propulsion system; and modifying, by the one or more computing devices, a speed relationship parameter defined between the first spool and second spool by providing electrical power to, or drawing electrical power from, an electric machine mechanically coupled to the first spool, the second spool, or both.