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 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.

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.

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 power conversion apparatus includes: a rotating electric machine that has a winding; an inverter that has a series-connection body of an upper arm switch and a lower arm switch; and a capacitor that is connected in parallel to the series-connection body. The power conversion apparatus includes: a connection path that, in a first storage battery and a second storage battery that are connected in series, electrically connects the winding with both a negative-electrode side of the first storage battery and a positive-electrode side of the second storage battery; and a control unit that controls switching of the upper arm switch and the lower arm switch such that a current flows between the first storage battery and the second storage battery through the inverter, the winding, and the connection path.

A power conversion apparatus includes: a rotating electric machine that has a winding; an inverter that has a series-connection body of an upper arm switch and a lower arm switch; and a capacitor that is connected in parallel to the series-connection body. The power conversion apparatus includes: a connection path that, in a first storage battery and a second storage battery that are connected in series, electrically connects the winding with both a negative-electrode side of the first storage battery and a positive-electrode side of the second storage battery; and a control unit that controls switching of the upper arm switch and the lower arm switch such that a current flows between the first storage battery and the second storage battery through the inverter, the winding, and the connection path.

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 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.

In an UPS system, following components are arranged in a machine cabinet: an AC-to-DC converter connected to a DC voltage link on its output side, a DC-to-AC converter connected to the DC voltage link on its input side; a motor/generator electrically connected to the DC voltage link and having a flywheel coupled to its rotor; a bypass to the AC-to-DC converter and the DC-to-AC converter connected in series, a bypass switch being arranged in the bypass; a controller; and a blower which draws air out of the surroundings through air filters, blows the air in the machine cabinet through a heat exchanger, and ejects the air again. The heat exchanger is arranged in a coolant circuit together with a coolant pump, cooling bodies for the power output stages, and coolant channels which include stator channels running through a stator of the motor/generator.

In an UPS system, following components are arranged in a machine cabinet: an AC-to-DC converter connected to a DC voltage link on its output side, a DC-to-AC converter connected to the DC voltage link on its input side; a motor/generator electrically connected to the DC voltage link and having a flywheel coupled to its rotor; a bypass to the AC-to-DC converter and the DC-to-AC converter connected in series, a bypass switch being arranged in the bypass; a controller; and a blower which draws air out of the surroundings through air filters, blows the air in the machine cabinet through a heat exchanger, and ejects the air again. The heat exchanger is arranged in a coolant circuit together with a coolant pump, cooling bodies for the power output stages, and coolant channels which include stator channels running through a stator of the motor/generator.