A hybrid-electric propulsion (HEP) system is provided that includes a gas turbine engine, an electrical power motive system, a system controller, and a propulsor. The gas turbine engine has a free turbine configuration and a compressor. The electrical power motive system has first and second electric motors and first and second inverters. The gas turbine engine provides motive force to the propulsor. The first electric motor is configurable in a drive mode or in generator mode. The second electric motor is in communication with the compressor. The system controller is in communication with the gas turbine engine, the first and second inverters, and a non-transitory memory storing instructions, which instructions cause the system controller to control the second inverter to operate the second electric motor to provide a motive force to the compressor of the gas turbine engine during a low power setting of the gas turbine engine.

An assembly for an aircraft propulsion system includes a propulsor, an electric motor, and an electrical distribution system. The electric motor is operably connected to the propulsor and operable to drive rotation of the propulsor. The electrical distribution system includes an electrical power source, an electrical cable, and a temperature protection assembly. The electrical cable electrically connects the electrical power source and the electric motor. The electrical cable extends through at least one thermal zone between the electrical power source and the electric motor. The temperature protection assembly includes a temperature sensor operable to sense a temperature in each thermal zone of the at least one thermal zone. The temperature protection assembly further includes a controller. The controller is configured to determine a zone temperature in the at least one thermal zone.

An engine system for an aircraft includes a gas turbine engine and a control system. The control system is configured to motor the gas turbine engine, absent fuel burn, during a taxi mode of the aircraft. The control system is further configured to accelerate a motoring speed of the gas turbine engine, absent fuel burn, above an idle speed of the gas turbine engine to provide propulsion during the taxi mode. The control system is configured to decrease the motoring speed of the gas turbine engine, absent fuel burn, based on a change in a starting mode of the gas turbine engine or the aircraft reaching a targeted new position.

An aircraft propulsion system is disclosed and includes a first gas turbine engine including a first input shaft driving a first gear system, a first fan driven by the first gear system, a first generator supported on the first input shaft and a fan drive electric motor providing a drive input to the first fan, a second gas turbine engine including a second input shaft driving a second gear system, a second fan driven by the second gear system, a second generator supported on the second input shaft and a second fan drive electric motor providing a drive input to the second fan and a controller controlling power output from each of the first and second generators and directing the power output between each of the first and second fan drive electric motors.

A hybrid-electric propulsion (HEP) system is provided that includes a gas turbine engine, an electrical power motive system, a system controller, and a propulsor. The gas turbine engine has a free turbine configuration and a compressor. The electrical power motive system has first and second electric motors and first and second inverters. The gas turbine engine provides motive force to the propulsor. The first electric motor is configurable in a drive mode or in generator mode. The second electric motor is in communication with the compressor. The system controller is in communication with the gas turbine engine, the first and second inverters, and a non-transitory memory storing instructions, which instructions cause the system controller to control the second inverter to operate the second electric motor to provide a motive force to the compressor of the gas turbine engine during a low power setting of the gas turbine engine.

A method of controlling a hybrid-electric aircraft powerplant includes running a first control loop for command of a thermal engine based on error between total response commanded for a hybrid-electric powerplant and total response from the hybrid-electric powerplant. A second control loop runs in parallel with the first control loop for commanding the thermal engine based on error between maximum thermal engine output and total response commanded. A third control loop runs in parallel with the first and second control loops for commanding engine/propeller speed, wherein the third control loop outputs a speed control enable or disable status. A fourth control loop runs in parallel with the first, second, and third control loops for commanding the electric motor with non-zero demand when the second control loop is above control to add response from the electric motor to response from the thermal engine to achieve the response commanded.

A hybrid propulsion unit for an aircraft with multi-rotor rotary wings includes an electrical generator driven by an internal combustion engine, a rectifier configured to convert an AC current sent by the electrical generator into DC current, a DC-AC converter, an electrical network connecting the rectifier to the converter and including a high-voltage DC current bus, electric motors powered by propeller converters coupled to the electric motors, electrical energy storage connected to the electrical network, the electrical storage including at least one primary storage element and at least one secondary storage element.

An engine assembly includes a propulsor, a first gearbox, an engine, a gas turbine engine, and a variable speed drive. The first gearbox includes a first gear assembly coupled with the propulsor. The engine includes an air inlet, an exhaust outlet, and an engine output shaft. The engine output shaft is coupled with the first gear assembly. The gas turbine engine includes a first rotational assembly, a compressor section, a turbine section, and a combustor. The first rotational assembly is configured for rotation about a rotational axis. The first rotational assembly includes a bladed compressor rotor, a bladed first turbine rotor, and a first shaft interconnecting the bladed compressor rotor and the bladed first turbine rotor. The compressor section is connected to the air inlet. The combustor is connected to the exhaust outlet. The VSD couples the first rotational assembly to the first gear assembly.

An electric power system for a vehicle includes at least one electric machine, one or more power rectifiers, and a plurality of DC channels. The at least one electric machine includes a plurality of tooth-wound multi-phase windings that are substantially magnetically decoupled, and the at least one electric machine is mechanically balanced even if one of the plurality of windings is de-energized. The one or more power rectifiers are configured to produce rectified power from the power generated by the at least one electric machine. The plurality of DC channels are formed after the at least one power rectifier and are configured to provide DC power to one or more loads within a vehicle.

An exemplary tiltrotor aircraft having a vertical takeoff and landing (VTOL) flight mode and a forward flight mode includes tiltable rotors located at forward boom ends, tiltable ducted fans located at wings aft of the forward boom ends, and aft rotors located on aft boom portions.