Methods and systems for operating a hybrid electric aircraft propulsion system. The method comprises providing alternating current (AC) electric power to a first electric motor to drive a first rotating propulsor, providing the first electric motor with AC electric power from at least one motor inverter operatively coupled to a direct current (DC) power source, detecting a failure in a path to the first electric motor, and selectively rearranging a first switching arrangement between the generator, the at least one motor inverter, and the first electric motor.

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 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 powertrain system includes an input element, an output element, and a magnetic transmission stage disposed directly at the output element. The magnetic transmission stage includes a first rotor with a first number of pole pairs, a second rotor with a second number of pole pairs, the second number of pole pairs being different from the first number of pole pairs, a third rotor with a number of pole bars arranged such that the magnetic field between the first and second pole pairs is modulated. A mechanical transmission stage is disposed between the magnetic transmission stage and the input element in the powertrain, and a control means controls a power flow between the input element and the output element. The control means is connected to a rotor of the magnetic transmission stage and to a shaft of the mechanical transmission stage.

A powertrain system includes an input element, an output element, and a magnetic transmission stage disposed directly at the output element. The magnetic transmission stage includes a first rotor with a first number of pole pairs, a second rotor with a second number of pole pairs, the second number of pole pairs being different from the first number of pole pairs, a third rotor with a number of pole bars arranged such that the magnetic field between the first and second pole pairs is modulated. A mechanical transmission stage is disposed between the magnetic transmission stage and the input element in the powertrain, and a control means controls a power flow between the input element and the output element. The control means is connected to a rotor of the magnetic transmission stage and to a shaft of the mechanical transmission stage.

A method of synchronizing a cross-compound generator system on one or more turning gears during startup includes determining, via a notch monitor controller, first and second angular velocities, respectively, of a first and a second rotor. The method also includes simultaneously exciting, via the notch monitor controller, the first and second rotors to attain electromechanical coupling therebetween. The method further includes determining, via the notch monitor controller, a value of a time at which a calibration value of an offset is a constant value, where the offset is representative of a phase alignment of the first rotor relative to the second rotor, and where the offset is indicative of a successful electromechanical coupling therebetween. The method also includes disengaging the one or more turning gears from the cross-compound generator system.

A method of synchronizing a cross-compound generator system on one or more turning gears during startup includes determining, via a notch monitor controller, first and second angular velocities, respectively, of a first and a second rotor. The method also includes simultaneously exciting, via the notch monitor controller, the first and second rotors to attain electromechanical coupling therebetween. The method further includes determining, via the notch monitor controller, a value of a time at which a calibration value of an offset is a constant value, where the offset is representative of a phase alignment of the first rotor relative to the second rotor, and where the offset is indicative of a successful electromechanical coupling therebetween. The method also includes disengaging the one or more turning gears from the cross-compound generator system.

A rotary electric system includes a rotary electric device that includes: a stator including a stator winding; and a rotor. The stator winding includes: a first coil group that generates a rotating magnetic field to rotate the rotor; and a second coil group that generates power with induced electromotive force due to rotation of the rotor.

A rotary electric system includes a rotary electric device that includes: a stator including a stator winding; and a rotor. The stator winding includes: a first coil group that generates a rotating magnetic field to rotate the rotor; and a second coil group that generates power with induced electromotive force due to rotation of the rotor.

A powertrain system includes an input element, an output element, and a magnetic transmission stage disposed directly at the output element. The magnetic transmission stage includes a first rotor with a first number of pole pairs, a second rotor with a second number of pole pairs, the second number of pole pairs being different from the first number of pole pairs, a third rotor with a number of pole bars arranged such that the magnetic field between the first and second pole pairs is modulated. A mechanical transmission stage is disposed between the magnetic transmission stage and the input element in the powertrain, and a control means controls a power flow between the input element and the output element. The control means is connected to a rotor of the magnetic transmission stage and to a shaft of the mechanical transmission stage.