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.

Two reduction gears have at least two common rotation center axes. A first power source (121) is coupled to the high-speed side of a first reduction gear (111) on a first rotation center axis (101). A second power source (122) is coupled to the high-speed side of a second reduction gear (112) on a second rotation center axis (102). A first input/output shaft (141) is coupled to the low-speed side of the second reduction gear (112) on the first rotation center axis (101). The high-speed side of the first reduction gear (111) is coupled to the low-speed side of the second reduction gear (112) on the first rotation center axis (101) via a first clutch (131). The low-speed side of the first reduction gear (111) is coupled to the high-speed side of the second reduction gear (112) on the second rotation center axis (102) via a second clutch (132).

A work vehicle including: a front wheel; a rear travel device; a travel body supported by the front wheel and the rear travel device; a driving section provided in the travel body and having an occupant floor section; a transmission configured to output power to the rear travel device; a transmission case housing the transmission; an electric motor coupled to the transmission; and an inverter connected to the electric motor, wherein: the inverter is provided between the front wheel and the rear travel device, under the floor section, and laterally of the transmission case.

A work vehicle including: a front wheel; a rear travel device; a travel body supported by the front wheel and the rear travel device; a driving section provided in the travel body and having an occupant floor section; a transmission configured to output power to the rear travel device; a transmission case housing the transmission; an electric motor coupled to the transmission; and an inverter connected to the electric motor, wherein: the inverter is provided between the front wheel and the rear travel device, under the floor section, and laterally of the transmission case.

A control device of a power supply circuit includes processing circuitry. The processing circuitry includes a state-of-charge calculator and a target calculator. The state-of-charge calculator calculate a state of charge of the first battery. The target calculator calculates a target voltage range. When an output voltage of the first battery detected by a voltage sensor cannot be acquired and an acquisition failure occurs, after the occurrence of the acquisition failure, the state-of-charge calculator is configured to obtain the state of charge of the first battery, as a held state-of-charge, that was calculated before the occurrence of the acquisition failure. When a pre-charge process is performed in a state in which the acquisition failure is occurring, the target calculator is configured to calculate an estimated output voltage of the first battery from the held state-of-charge and calculate the target voltage range based on the estimated output voltage.

In an aspect of the disclosure, a method, a computer-readable medium, and an apparatus are provided. The apparatus may be a vehicle power system, which includes an electric motor, a primary power source that energizes the electric motor, wherein the primary power source employs a turbine to generate electricity, a second power source that supplements the primary power source to energize the electric motor, and a control component that monitors power provided to the electric motor by the primary power source, that determines that additional power needs to be provided to the electric motor in order to meet a driving requirement, and that directs additional power from the second power source to the electric motor.

In an aspect of the disclosure, a method, a computer-readable medium, and an apparatus are provided. The apparatus may be a vehicle power system, which includes an electric motor, a primary power source that energizes the electric motor, wherein the primary power source employs a turbine to generate electricity, a second power source that supplements the primary power source to energize the electric motor, and a control component that monitors power provided to the electric motor by the primary power source, that determines that additional power needs to be provided to the electric motor in order to meet a driving requirement, and that directs additional power from the second power source to the electric motor.

In an electric drive system in which a battery is not connected to a DC bus, even when a load on a traveling electric motor increases suddenly, it is made possible to avoid such a situation that the DC bus voltage drops to a level equal to or lower than an operating voltage of an inverter and the inverter stops working. To this end, a DC bus voltage drop prevention device controls such that, when the voltage of the DC bus drops below a first threshold value, the output torque of the traveling electric motor is decreased according to an amount of decrease in the voltage of the DC bus, and when the voltage of the DC bus drops below a second threshold voltage lower than the first threshold voltage, the output torque of the traveling electric motor is decreased to zero or a value within a range of magnitude with which a work vehicle stays stationary on a level ground.

An electric system of an electromechanical power transmission chain is provided that includes a first capacitive circuit, converter equipment between the first capacitive circuit and an electric machine, a second capacitive circuit, and a direct voltage converter between the first and second capacitive circuits. The electromechanical power transmission chain is a parallel transmission chain where the electric machine is mechanically connected to a combustion engine and to one or more actuators. The electric system includes a control system for controlling the direct voltage converter in response to changes in a first direct voltage of the first capacitive circuit and for controlling the converter equipment in response to changes in a second direct voltage of the second capacitive circuit. The first direct voltage is kept on a predetermined voltage range whereas the second direct voltage is allowed to fluctuate in order to respond to peak power needs.