A system for generating power includes a turbine generator for generating alternating current (AC) power and a power electronics module that provides a first signal to the turbine generator to switch an operating mode of the turbine generator from an off mode to a startup mode. The first signal is variable frequency power. The system includes a controller that provides a second signal that causes the turbine generator to switch from a normal operating mode to a coast down mode. In the startup mode, the turbine generator accelerates to a full rotational rate and in the coast down mode, the turbine generator decelerates from the full rotational rate to a stop over an interval of time. The system includes a power converter that converts rotational inertia by the turbine generator into direct current (DC) power responsive to the turbine generator operating in the coast down mode.

There is provided a hybrid electric aircraft propulsion system and method for operating same. The method comprises providing, to a first electric motor and a second electric motor, alternating current (AC) electric power from a generator, the generator receiving rotational power from a thermal engine, providing, to the first electric motor and the second electric motor, AC electric power from at least one motor inverter, the at least one motor inverter configured to convert DC electric power from a DC power source into AC electric power, and selectively driving the first and second electric motors from the generator, the at least one motor inverter, or a combination thereof, wherein the first electric motor drives a first rotating propulsor and the second electric motor drives a second rotating propulsor.

Reconfigurable permanent magnet electrical machines and aircraft power and propulsion systems including the electrical machines. An aircraft power and propulsion system includes: a gas turbine engine; DC electrical network; permanent magnet electrical machine including a rotor drivingly coupled to a spool of the engine, and a stator including windings controllably switchable between a star and a delta configuration; an AC-DC power electronics converter, an AC side is connected to terminals of the stator windings and a DC side is connected to the DC electrical network; an additional electrical power source connected to and controllable to supply electrical power to the DC electrical network; and a control system configured to control the switching of the stator windings between the configurations and to control the additional electrical power source to supply electrical power to the DC electrical network during a time interval when the stator is being switched between the configurations.

Various embodiments that pertain to fuel processing are described. A fuel processor can produce an endothermic reaction that cools a substance and produces a processed fuel from a raw fuel. A generator can employ the processed fuel to produce an electricity. The generator can supply the electricity to a load that uses the electricity to function. The load can become hot due to its functioning and can benefit from being cooled. The substance cooled by the fuel processor can cool load and in the process the substance can rise in temperature. This warmer substance can be transferred to the fuel processor to be cooled again and this cycle can continue. Further, the fuel processor can use the warmer substance to achieve the endothermic reaction.

A control device includes a first rotational speed acquisition unit (acquisition unit) that acquires a first rotational speed, which is the rotational speed of a gas turbine engine, based on a signal supplied from a rotational speed sensor, a second rotational speed acquisition unit (acquisition unit) that acquires a second rotational speed, which is the rotational speed of a power generator, based on a signal supplied from a rotation angle sensor, a comparison unit that compares the first rotational speed with the second rotational speed, and a control unit that controls the gas turbine engine and the power generator based on the lower one of the first rotational speed and the second rotational speed based on a comparison result by the comparison unit.

A retrofit gas turbine engine includes a compressor, a combustor and a turbine. A tie shaft is connected to rotate by the turbine, and provide rotational drive into a gearbox. At least one fuel pump is connected to be driven by the gearbox. The at least one fuel pump delivers fuel downstream toward the combustor, and also has a return line. An added accessory turbine is positioned on the return line, and drives an added accessory which has been retrofit added to an existing gas turbine engine. A method is also disclosed.