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 has been a drawback in that current command values need to be set for a current command unit of a power conversion device in accordance with efficiency, and thus the number of operation steps increases. In the power conversion device connected between a three-phase AC rotating machine and a DC power supply and configured to convert DC power into AC power, a DC voltage value, of the DC power supply, that is to be inputted to a current command unit of the power conversion device is corrected on the basis of an efficiency index, and a current command value to be outputted by the current command unit is changed on the basis of the corrected DC voltage value and a torque command value, whereby the efficiencies of the power conversion device and the three-phase AC rotating machine are controlled.

There has been a drawback in that current command values need to be set for a current command unit of a power conversion device in accordance with efficiency, and thus the number of operation steps increases. In the power conversion device connected between a three-phase AC rotating machine and a DC power supply and configured to convert DC power into AC power, a DC voltage value, of the DC power supply, that is to be inputted to a current command unit of the power conversion device is corrected on the basis of an efficiency index, and a current command value to be outputted by the current command unit is changed on the basis of the corrected DC voltage value and a torque command value, whereby the efficiencies of the power conversion device and the three-phase AC rotating machine are controlled.

An electrical power system for a watercraft including a first electrical power plant configured to operate in a variable frequency mode to output variable frequency power to a first electrical network and a fixed frequency mode to output fixed frequency power to a second electrical network. There is a first electrical load including a first high temperature superconductor (HTS) motor connected to the first electrical network and a second electrical load connected to a second electrical network. A controller selectively connects the first electrical power plant to the first electrical network and operates the first electrical power plant in a variable frequency mode to output variable frequency power to power the first HTS motor and selectively connects the first electrical power plant to the second electrical network and operates the first electrical power plant in a fixed frequency mode to output fixed frequency power to power the second electrical load.

An electrical power system for a watercraft including a first electrical power plant configured to operate in a variable frequency mode to output variable frequency power to a first electrical network and a fixed frequency mode to output fixed frequency power to a second electrical network. There is a first electrical load including a first high temperature superconductor (HTS) motor connected to the first electrical network and a second electrical load connected to a second electrical network. A controller selectively connects the first electrical power plant to the first electrical network and operates the first electrical power plant in a variable frequency mode to output variable frequency power to power the first HTS motor and selectively connects the first electrical power plant to the second electrical network and operates the first electrical power plant in a fixed frequency mode to output fixed frequency power to power the second electrical load.

A main converter (i) converts AC power from a generator at a primary terminal into DC power at a secondary terminal, an internal combustion engine driving the generator to generate the AC power, or (ii) converts DC power at the secondary terminal into AC power and supplies the AC power to the generator. A first inverter is connected to the secondary terminal of the main converter. A step-down circuit steps down a voltage of the DC power output by the main converter and supplies the stepped-down DC power to a power storage device. The generator, using the power storage device as an electric power source, operates as an electric motor to start the internal combustion engine. After the internal combustion engine is started, the DC power output by the main converter is supplied to the first inverter, stepped down by the step-down circuit, and supplied to the power storage device.

A main converter (i) converts AC power from a generator at a primary terminal into DC power at a secondary terminal, an internal combustion engine driving the generator to generate the AC power, or (ii) converts DC power at the secondary terminal into AC power and supplies the AC power to the generator. A first inverter is connected to the secondary terminal of the main converter. A step-down circuit steps down a voltage of the DC power output by the main converter and supplies the stepped-down DC power to a power storage device. The generator, using the power storage device as an electric power source, operates as an electric motor to start the internal combustion engine. After the internal combustion engine is started, the DC power output by the main converter is supplied to the first inverter, stepped down by the step-down circuit, and supplied to the power storage device.

An electric power system for a vehicle includes at least one electric machine, one or more power rectifiers, and a plurality of DC channels. The at least one electric machine includes a plurality of tooth-wound multi-phase windings that are substantially magnetically decoupled, and the at least one electric machine is mechanically balanced even if one of the plurality of windings is de-energized. The one or more power rectifiers are configured to produce rectified power from the power generated by the at least one electric machine. The plurality of DC channels are formed after the at least one power rectifier and are configured to provide DC power to one or more loads within a vehicle.

An object of the present invention is to provide a drive system for a dump truck capable of suppressing increase in size of a converter that controls a two-winding induction generator. To this end, the drive system for a dump truck includes a DC-DC converter connected to a main side DC bus and an auxiliary side DC bus, and a controller controls the DC-DC converter such that electric power of the main side DC bus is supplied to the auxiliary side DC bus via the DC-DC converter.

An object of the present invention is to provide a drive system for a dump truck capable of suppressing increase in size of a converter that controls a two-winding induction generator. To this end, the drive system for a dump truck includes a DC-DC converter connected to a main side DC bus and an auxiliary side DC bus, and a controller controls the DC-DC converter such that electric power of the main side DC bus is supplied to the auxiliary side DC bus via the DC-DC converter.