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 windshield wiper system (WWS) is provided. The WWS includes a brushless direct current (BLDC) motor, a wiper arm and blade, a gearbox/converter operably interposed between the BLDC motor and the wiper arm and blade and a smart motor drive configured to determine a WWS failure condition and to operate the BLDC motor according to the determination.

The disclosure relates to an electric machine and in particular to the monitoring of the electric machine for the presence of a fault, (e.g., in the stator windings). A monitoring unit is provided, wherein the monitoring unit measures the multiphase electrical time signals transmitted from or to the machine and with the aid of a Hilbert filter determines substantially in real time the envelopes and the phase positions of the individual phases of the time signal. The envelopes corresponding to the different phases or the corresponding phase positions are compared with one another by way of forming differences and, in the event that one or more of the differences deviate(s) from a specified expectation value, the presence of a fault is inferred. The approach allows significantly increased operational reliability of the electric machine to be achieved in particular.

A turbo-generator system for generating propulsive electrical power for an aircraft includes an electric machine comprising: a rotor configured to be rotated by a gas-turbine of the turbo-generator system; a stator comprising: a first active section comprising first windings surrounding a first portion of the rotor; and a second active section comprising second windings surrounding a second portion of the rotor.

A propulsion channel for aircraft at least one first dual-fed polyphase asynchronous rotating electric machine configured to be mechanically coupled to a turbine engine. The propulsion channel further includes at least one second polyphase rotating electric machine electrically coupled to the first asynchronous rotating electric machine, and a control and storage module configured to control the first polyphase asynchronous rotating electric machine. The module is connected to the first dual-feed polyphase asynchronous rotating electric machine as well as to the at least second polyphase rotating electric machine. The at least second polyphase rotating electric machine includes a polyphase synchronous rotating electric machine with permanent magnet.

Controlling a DC-AC inverter of an electric machine, where the electric machine comprises a resonant main exciter having rotary transformer. A voltage level of DC power received at a DC-AC inverter is monitored and the frequency of AC power generated by the DC-AC inverter and supplied to the rotary transformer is controlled based at least in part on the voltage level of the DC power.

Systems and methods for voltage regulation of high voltage direct current systems are provided. In certain embodiments, a system includes a generator that generates alternating current (AC) voltage. The system further includes a power converter that converts the AC voltage into regulated direct current (DC) voltage. Also, the system includes a voltage regulator. In additional embodiments, the voltage regulator includes an AC voltage regulator that regulates the AC voltage generated by the generator. Also, the voltage regulator includes a DC voltage regulator that regulates the DC voltage produced by the power converter. Moreover, the voltage regulator includes a regulator selector that selectively activates one of the AC voltage regulator and the DC voltage regulator based on a current from the power converter and at least one of a voltage of the generator and a voltage of the power converter.

There is described a method and system for operating a hybrid electric aircraft propulsion system. The method comprises modulating AC electric power applied to a first electric propulsor or a second electric propulsor from at least one motor inverter to synchronize the frequency of the first electric propulsor or the second electric propulsor with the frequency of a generator.

A method of controlling a variable speed constant frequency (VSCF) power converter is provided. The method includes receiving a determination that a sensed AC current output has exceeded a predetermined limit. The AC current output is converted from a DC voltage and has a constant frequency. The DC voltage is converted from a variable frequency AC voltage. The variable frequency AC voltage is generated in response to a mechanical energy input having a varying parameter. The method further includes decreasing the DC voltage in response to a determination that the sensed AC current output has exceeded the predetermined limit.

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.