A hybrid electric aircraft propulsion system includes both a turbine engine and an electric motor. A power management system controls operation of the electric motor and a pitch angle of a propeller associated with the propulsion system. A disconnect switch is provided to isolate the electric motor by mechanical decoupling the electric motor from the aircraft propulsion system.

An electromechanically controlled aircraft power transmission system includes a first planetary gear set, a first gas turbine engine, a first electric machine, a second planetary gear set, a second gas turbine engine, a second electric machine, a propulsor shaft, and at least one propulsor. The first gas turbine engine is coupled to the first planetary gear set. The first electric machine is coupled to the first planetary gear set and is configured vary the gear ratio of the first planetary gear set. The second gas turbine engine is coupled to the second planetary gear set. The second electric machine is coupled to the second planetary gear set and is configured to vary the gear ratio of the second planetary gear set. The propulsor shaft is coupled to the first and second planetary gear sets and the at least one propulsor is coupled to the propulsor shaft.

A hybrid powertrain system and method includes a prime mover driving a generator/motor to produce an AC power output. The AC power output is applied to a rectifier which is controlled to transform the applied AC power to DC power to supply a DC Power bus at a selected voltage and current. An energy storage device is also connected to the DC power bus and the current flow between the energy storage device and the DC power bus is monitored and compared to preselected values and the results of that comparison are used to alter the operation of the rectifier to increase or decrease, as needed, the current provided to the DC power bus as electrical loads on the DC power bus change.

A hybrid-electric aircraft system is provided and includes first and second hybrid-electric engines, each of which includes an electric motor to drive operations thereof, and a supplemental power unit (SPU). The SPU is configured as a thermal engine paired with a generator and is configured to generate electrical power. The first and second hybrid-electric engines are operable normally and off, respectively, with electrical power generated by the SPU being diverted to the electric motor of the second hybrid-electric engine.

A method is provided for operating a propulsion system having a gas turbine engine and a fuel cell assembly. The fuel cell assembly includes a fuel cell. The method includes: receiving gas composition data of output products from the fuel cell; and controlling operation of the fuel cell assembly, the gas turbine engine, or both in response to the received gas composition data of the output products from the fuel cell.

A method is provided for operating a propulsion system having a gas turbine engine and a fuel cell assembly. The fuel cell assembly includes a fuel cell. The method includes: receiving gas composition data of output products from the fuel cell; and controlling operation of the fuel cell assembly, the gas turbine engine, or both in response to the received gas composition data of the output products from the fuel cell.

A method of braking a rotational air mover portion of an aircraft propulsion system is provided. The method includes: using an electrical device to apply a torque to a propulsion unit driven by a propulsion system of an aircraft, the propulsion unit including a rotational air mover configured to provide thrust for propelling the aircraft, wherein the electrical device is configured to produce electrical energy during the process of applying the torque to the propulsion unit; controlling the electrical device to apply an amount of the torque that is sufficient to cause the rotational air mover to decelerate or to maintain the rotational air mover non-rotational; and directing the electrical energy produced by the electrical device to an aircraft component.

A method of braking a rotational air mover portion of an aircraft propulsion system is provided. The method includes: using an electrical device to apply a torque to a propulsion unit driven by a propulsion system of an aircraft, the propulsion unit including a rotational air mover configured to provide thrust for propelling the aircraft, wherein the electrical device is configured to produce electrical energy during the process of applying the torque to the propulsion unit; controlling the electrical device to apply an amount of the torque that is sufficient to cause the rotational air mover to decelerate or to maintain the rotational air mover non-rotational; and directing the electrical energy produced by the electrical device to an aircraft component.

A power supply device includes a power generator, a drive source, a plurality of power supply lines, a plurality of batteries, a difference calculating unit 11, a difference summing unit 12, and an electric power summing unit 13. The difference calculating unit 11 is configured to calculate differences D1, D2, D3, and D4 between a target charge state set for each battery and an estimated charge state. The difference summing unit 12 is configured to sum the differences D1, D2, D3, and D4 calculated by the difference calculating unit 11. The electric power summing unit 13 is configured to sum the charge state calculated by the difference summing unit 12 and electric power used for the electric loads. A control unit 9 controls the drive source such that electric power calculated by the electric power summing unit 13 is generated by the power generator.

A power supply device includes a power generator, a drive source, a plurality of power supply lines, a plurality of batteries, a difference calculating unit 11, a difference summing unit 12, and an electric power summing unit 13. The difference calculating unit 11 is configured to calculate differences D1, D2, D3, and D4 between a target charge state set for each battery and an estimated charge state. The difference summing unit 12 is configured to sum the differences D1, D2, D3, and D4 calculated by the difference calculating unit 11. The electric power summing unit 13 is configured to sum the charge state calculated by the difference summing unit 12 and electric power used for the electric loads. A control unit 9 controls the drive source such that electric power calculated by the electric power summing unit 13 is generated by the power generator.