A hybrid electric propulsion system includes a gas turbine engine having a low speed spool and a high speed spool. The low speed spool includes a low pressure compressor and a low pressure turbine, and the high speed spool includes a high pressure compressor and a high pressure turbine. The hybrid electric propulsion system also includes an energy storage system, an electric motor configured to augment rotational power of the high speed spool, and a controller. The controller is operable to detect a start condition of the gas turbine engine, control power delivery from the energy storage system to the electric motor based on detecting the start condition, and provide a compressor stall margin using a power-assist provided by the electric motor to the high speed spool over a targeted speed range during starting of the gas turbine engine.

A system for estimating the angular position of a rotating shaft in an aircraft, the system including at least three electromagnetic effect sensors. The system including a flight controller that runs a voting algorithm, wherein the voting algorithm computes an output datum based on shaft position datum that qualify as both active and admissible. Furthermore, system may include, as a component of the voting algorithm, a banning process where sensors that repeatedly return datum that are either not active or not admissible can be banned.

An assistance method for assisting a pilot of a single-engined rotary-wing aircraft during a flight phase in autorotation, the aircraft including a hybrid power plant provided with a main engine, with an electric machine, with a main gearbox, and with an electrical energy storage device. The aircraft also includes a main rotor driven by the hybrid power plant. In the method, during a flight, operation of the main engine is monitored in order to detect a failure, in particular by means of a drop in power on the main rotor, then, when a failure of the main engine is detected, the electric machine is controlled to deliver auxiliary power We to the main rotor, making it possible to assist a pilot of the aircraft in performing the flight phase in autorotation following the failure.

An AC to DC conversion device has first and second AC input terminals arranged to be coupled respectively to first and second terminals of a phase of an AC current generator, an H-bridge rectification device comprising two pairs of diodes, each pair being coupled to a respective one of the AC terminals to produce a DC output comprising a rectified back EMF waveform, and a waveform generator. The waveform generator comprises an output coupled to the DC output of the H-bridge rectification device, and is configured to input a unidirectional waveform to the DC output having the same magnitude and fundamental frequency as the rectified back EMF, phase shifted by a predetermined angle relative to the rectified back EMF waveform.

Apparatus and associated methods relate to active damping of mechanical oscillations of a synchronous generator's drivetrain by modulating an excitation signal provided to the synchronous generator in proper phase relation with detected mechanical oscillations so as to dampen these oscillations. The excitation signal includes a superposition of a voltage-regulation signal and an active-damping signal. The voltage-regulation signal is configured to regulate an output voltage of electrical power provided by the synchronous generator, and the active-damping signal is configured to provide active damping to the drivetrain of the mechanical system that includes the synchronous generator. The active-damping signal is generated by detecting mechanical oscillations of the drivetrain, filter such detected mechanical oscillations such that the active-damping signal has a proper phase relationship with the mechanical oscillations over a predetermined range of frequencies. This proper phase relationship is maintained over the range of frequencies using a second order lag/lead filter.

A system includes a first AC bus configured to supply power from a first generator. A first generator line contactor (GLC) selectively connects the first AC bus to the first generator. A second AC bus is configured to supply power from a second generator. A second GLC selectively connecting the second AC bus to the second generator. An auxiliary generator line contactor (ALC) is connected to selectively supply power to the first and second AC buses from an auxiliary generator. A first bus tie contactor (BTC) electrically connects between the first GLC and the ALC. A second BTC electrically connects between the ALC and the second GLC. A ram air turbine (RAT) automatic deployment controller is operatively connected to automatically deploy a RAT based on the combined status of the first GLC, the second GLC, the ALC, the first BTC, and the second BTC.

An AC electrical system for a vehicle and methods of operating the same are provided. In one aspect, an AC electrical system includes a first electric machine mechanically coupled with a first spool of a gas turbine engine and a second electric machine mechanically coupled with a second spool of the gas turbine engine. The system also includes a first AC bus and a second AC bus. A first electrical channel electrically couples the first electric machine to the first AC bus and a second electrical channel electrically couples the second electric machine to the second AC bus. The system also includes one or more connection links and one or more power converters for selectively electrically coupling the first and second electrical channels so that electrical power generated by one electric machine can be converted and shared with the other electric machine and electrical loads of the other channel.

A generator system can include a generator configured to produce an output of alternating current (AC), a rectifier connected to the generator to rectify the AC into direct current (DC) rectifier output, an inverter connected to the rectifier to receive the DC rectifier output and configured to output three phase AC inverter output, and a plurality of output lines connected to the inverter to receive the three phase AC inverter output. The system can include a control module configured to control the output of the inverter. The control module can be operatively connected to one or more of the output lines via one or more local sense leads to receive a local feedback. The control module can be configured to control the inverter as a function of the local feedback to provide one or more of protection, voltage regulation, or harmonic correction.

An engine system includes a turbine engine having a high pressure spool and a low pressure spool. A transmission includes an input shaft connected to one of the high pressure spool and the low pressure spool, and an output shaft. A clutch is arranged between the input shaft and the output shaft. A generator is connected to the output shaft. A clutch controller activates the clutch when one of the high pressure spool and the low pressure spool, and the generator are operating at a selected speed range.

Systems and methods for dual voltage power generation are provided. Aspects include a generator having an input connected to an engine to receive rotational energy proportional to a rotation speed of a fan and having an output through which electrical energy is output, a rectifier circuit having an input coupled to the output of the generator and a rectifier output that outputs rectified power, a bypass switch connected to the output of rectifier and operates in a plurality of states including a normal operation state where the rectified power is provided a power converter and a bypass state where the rectified power is provided directly to a load, and a controller configured to determine an occurrence of an event associated with the engine, and operate the bypass switch in the bypass state based on the occurrence of the event associated with the engine.