An electric driving wheel type work vehicle has a traveling motor, an inverter for supplying the motor with three-phase power converted from DC power, a pre-driver circuit for supplying a gate signal to the inverter on the basis of an input PWM signal, a controller for outputting to the pre-driver circuit the PWM signal for controlling the driving of the motor, a parking brake, and a parking brake condition detector that detects the condition of the parking brake. When it is detected that the parking brake has been operated, the pre-driver circuit cuts off the output of the gate signal or the input of the PWM signal to the pre-driver circuit.

The invention relates to a converter (1) comprising an intermediate circuit (3) for providing a DC voltage (10) between a positive conductor (11) and a negative conductor (12), a phase conductor (8, 9) for receiving and/or output of an AC voltage, and a half-bridge circuit (17) comprising a first switch arrangement (18) for connecting the positive conductor (11) to the phase conductor (8, 9) and a second switch arrangement (19) for connecting the negative conductor (12) to the phase conductor (8, 9). In case of a defect of a semiconductor switch (20, 21) of the converter (1), the converter (1) is to be able to protect itself and continue to operate. For this purpose, the first switch arrangement (18) and the second switch arrangement (19) respectively have a parallel connection made of multiple switching branches (Z) and, in each switching branch (Z), one of the semiconductor switches (20, 21) is provided with an intrinsic safety fuse (22) switched in series to the contact gap of the semiconductor switch (20, 21).

A vehicle controlling system includes a high-voltage circuit including a motor for driving a vehicle and a generator driven by an engine; an intermediate-voltage circuit including a battery and having a potential lower than the potential of the high-voltage circuit; a low-voltage circuit having a potential lower than the potential of the intermediate-voltage circuit, accessories being disposed to the low-voltage circuit; a transformer disposed between the high-voltage circuit and the intermediate-voltage circuit; and a down converter disposed between the intermediate-voltage circuit and the low-voltage circuit. The controlling system further includes a generator controller to control the generator such that the generator generates power equal to or higher than the sum of power consumed by the motor and power output from the transformer to the intermediate-voltage circuit at a temperature of the battery lower than a predetermined temperature, and a transformer controller to control the transformer such that the transformer outputs power equal to or lower than power output from the down converter to the low-voltage circuit at a temperature of the battery lower than the predetermined temperature.

A hybrid work vehicle includes a work device, a traveling drive device, a lever operation quantity detection unit, an engagement state detection unit, a pedal operation quantity detection unit, a travel state detection unit, and an engine control unit. The engine control unit controls an engine rotation rate based upon at least either the lever operation quantity or the pedal operation quantity in correspondence to either the engaged state or the non-engaged state and either the traveling state or the non-traveling state.

A braking distance control device employed for an electrically driven work vehicle includes a safety vehicle speed calculation unit 9 that calculates a safety vehicle speed at which a braking distance provided by use of an electric brake device becomes less than or equal to a threshold value, based on gradient information, payload information, road surface friction information, vehicle speed information, and a braking torque characteristic of electric motors. Preferably, the braking distance control device includes: a critical vehicle speed for deceleration calculation unit 5 that calculates a critical vehicle speed for deceleration at which deceleration provided by use of the electric brake device becomes less than or equal to a threshold value; a vehicle speed judgment unit 8 that judges whether the work vehicle can be stopped within a set distance by the electric brake device, based on result of comparing the vehicle speed information with the safety vehicle speed and the critical vehicle speed for deceleration; a notification command unit 17 that calls the operator's attention or prompts a brake operation, based on the result of the judgment; an operation judgment unit 14 that judges a setting of notification, based on pedal operation amounts; and a logical product calculation unit 15 that outputs a setting of a notification operation, based on result of the judgments by the vehicle speed judgment unit 8 and the operation judgment unit 14.

A control system for controlling power supply of an electric machine of an automobile and which contributes to movement thereof, wherein the control system is connected, at an input thereof, to a mechanism estimating a temperature of a rotor of the electric machine and to a temperature sensor measuring a temperature of a stator of the electric machine. The control system includes mappings of a set of values for allocating supply currents of the electric machine on the basis of torque and rotational speed request values received at the input of the control system, and includes a switching mechanism for selecting the mapping, the supply current signals of which are transmitted to the electric machine, on the basis of the signals from the mechanism estimating the temperature of the rotor and from the stator-temperature sensor.

A hybrid vehicle control device is provided for controlling a drive system in a hybrid vehicle. The hybrid vehicle control device is provided with a hybrid control module that controls an operation start timing of a DC/DC converter at vehicle startup. When an ignition switch is pressed, after connecting a high power relay that is interposed between the motor/generator and the high power battery, the hybrid control module starts operation of the DC/DC converter upon determining that the outputtable electric power by the high power battery is a prescribed value or greater.

An electric drive retrofit kit includes a rear entry electric drive motor module that includes an electric drive planetary gear assembly and a second electric drive planetary gear assembly which can be inserted into a rear final drive cavity of a frame housing for a tracked tractor with a high track drive. The electric drive retrofit kit may further include a generator, a cooling package, an additional water pump, a steering pump, a steering motor, power inverters with control modules, and electric cables.

In a power conversion apparatus, an inverter converts a DC voltage supplied from a battery into an AC voltage, and a DC-to-DC converter steps up or down the DC voltage. A case has an input terminal to which a power line from the battery is connected so as to input the DC voltage to the inverter, and a converter input terminal to which a power line to the DC-to-DC converter is connected so as to input the DC voltage to the DC-to-DC converter. The case has a reference wall and an opposed wall opposed to each other. The inverter input terminal is disposed adjacent to the reference wall with respect to an imaginary plane that bisects the case between the reference wall and the opposed wall. The converter input terminal is disposed adjacent to the opposed wall with respect to the imaginary plane.

A work machine includes: a controller; a first electrical circuit provided with a first power supply that supplies power to the controller; an electric drive source necessary for operating the work machine; and a second electrical circuit provided with a second power supply that supplies power to the electric drive source. The work machine further includes: a capacitor provided to the second electrical circuit; a first precharge device that performs precharge of the capacitor by using power of the first power supply; and a second precharge device that performs precharge of the capacitor by using power of the second power supply. The controller performs precharge by using one of the precharge devices when it is determined that precharge by using the other one of the precharge devices is impossible.