A hybrid electric aircraft propulsion system and method of operation are described. The system comprises a thermal engine, a generator coupled to the thermal engine, a first electric propulsor operatively connected to the generator to receive alternating current (AC) electric power therefrom, a second electric propulsor, a generator inverter operatively connected to the generator to convert AC electric power to direct current (DC) electric power, and a first motor inverter operatively connected to the generator inverter and selectively connected to one of the first electric propulsor and the second electric propulsor and configured to receive the DC electric power and provide the first electric propulsor and the second electric propulsor with AC electric power, respectively.

A system includes a gas turbine operational at a constant rated rotational speed, a speed sensor to measure an actual speed of the gas turbine, a turbine controller to control the gas turbine to the constant rated rotational speed, and a generator coupled with the gas turbine and rotatable to output electric power. The system also includes a DC to DC converter to output a load current on a load bus to supply a load. The DC to DC converter is supplied input electric power from the generator. The system also includes an energy storage device cooperative operable with the DC to DC converter to supply power on the load bus, and a controller to receive the actual speed and adjust an output electrical current set point of the DC to DC converter to compensate for deviation of the actual speed from the constant rated speed of the gas turbine.

A load adaptive linear electrical generator system is provided for generating DC electrical power. The electrical generation system includes one or more power generation modules which will be selectively turned on or off and additively contribute power depending on the DC power demand. Each power generating module includes a pair of linear electrical generators connected to respective ones of a pair of internal combustion piston based power assemblies. The piston in the internal combustion assembly is connected to a magnet in the linear electrical generator. The piston/magnet assembly oscillates in a simple harmonic motion at a frequency dependent on a power load of the electrical generator. A stroke limiter constrains the piston/magnet assembly motion to preset limits.

An uninterruptible power supply system has a regulated power source, an electrical generator electrically interconnected to the regulated power source, an engine having a main shaft integral with or coupled to the shaft of the electrical generator, a rotating rectifier mounted onto a shaft of the electrical generator, a mains power supply, a switch connected between the electrical generator, the mains power supply and a synchronous machine of the regulated power source, a synchronous generator, and an uninterruptible load. The regulated power source has a housing, a synchronous machine, a synchronous generator, and a flywheel sharing a common shaft. The electrical generator has a shaft coupled to a combustion engine. The switch transfers power from the synchronous machine to the electrical generator to cause the electrical generator to rotate its shaft or the main shaft of the engine. A short-stop load is supplied power from the electrical generator.

Systems and methods for improving shifting of a transmission are described. The systems and methods may be applied to automatic or manual transmissions, but the systems and methods may be particularly suited for automatic transmissions. In one example, electrical input to an alternator and electrical output from the alternator is adjusted in response to a request to upshift a transmission.

A vehicle mounted AC generator system having an AC generator mounted driven by the vehicle's power-take off having a secure control system. The secure control system integrates with the AC generator, the power-take off and the vehicle to enable the generator to be operated by the vehicle's engine while the cab or passenger compartment of the vehicle remains secured, thereby preventing the potential for theft or accidental input which may create a dangerous condition. The secure control system also provides monitoring of the generator's operation and emergency stop capability to shut down both the generator and the vehicle's engine in the event required.

Exhaust gases from an engine, input to turbo-compounder, drive a bladed turbine rotor therein, which drives a multi-phase AC generator, the output of which is used to electrically drive a multi-phase induction motor, the rotor of which is mechanically coupled to the engine, so as to provide for recovering power to the engine. The multi-phase AC generator may be coupled to the engine either by closure of a contactor, engagement of an electrically-controlled clutch, or by control of either a solid-state switching or control system or an AC excitation signal, when the frequency (f.sub.GENERATOR) of the multi-phase AC generator meets or exceeds that (f.sub.MOTOR) of the multi-phase induction motor.

Exhaust gases from an engine, input to turbo-compounder, drive a bladed turbine rotor therein, which drives a multi-phase AC generator, the output of which is used to electrically drive a multi-phase induction motor, the rotor of which is mechanically coupled to the engine, so as to provide for recovering power to the engine. The multi-phase AC generator may be coupled to the engine either by closure of a contactor, engagement of an electrically-controlled clutch, or by control of either a solid-state switching or control system or an AC excitation signal, when the frequency (f.sub.GENERATOR) of the multi-phase AC generator meets or exceeds that (f.sub.MOTOR) of the multi-phase induction motor.

A switch can connect or disconnect a generator and a supply unit. A control unit controls an engine in one of a plurality of control states including a power generation state, a first standby state and a second standby state. When an acceptance unit accepts a switching instruction from the first standby state to the second standby state, the control unit controls the switch to disconnect the generator and the supply unit, and reduces the engine speed of the engine from an engine speed in the first standby state to an engine speed in the second standby state.

Systems and methods for starting a gas turbine engine can comprise a generator to be driven by the gas turbine engine to supply power to a grid system, a first switch to electrically couple and decouple the generator from the grid system, a first static frequency converter having a first capacity, a second static frequency converter having a second capacity, control means for electrically coupling and decoupling the first and second static frequency converters from the grid system, a synchronizer and a controller configured to operate the generator as a starter-motor with power from: the first static frequency converter to turn the gas turbine engine at a first rate sufficient to start the gas turbine engine within a first time period or the first static frequency converter and the second static frequency converter in synchronization to turn the gas turbine engine at a second rate greater than the first rate.