A vehicle power supply device converts power from high voltage to low voltage by selectively connecting a predetermined power storage element group to a low voltage electric load from a high voltage power supply formed by connecting power storage elements in series. A leakage current from the high voltage power supply is measured during the dead time period when the power storage element group is not connected to the low voltage electric load. When the value exceeds a predetermined value, the connection between the power storage element group and the low-voltage electric load is interrupted, so that electric shock is prevented.

A vehicle power supply device converts power from high voltage to low voltage by selectively connecting a predetermined power storage element group to a low voltage electric load from a high voltage power supply formed by connecting power storage elements in series. A leakage current from the high voltage power supply is measured during the dead time period when the power storage element group is not connected to the low voltage electric load. When the value exceeds a predetermined value, the connection between the power storage element group and the low-voltage electric load is interrupted, so that electric shock is prevented.

A vehicle communication, power, and guidance system for use in guiding and communicating with a land vehicle along a roadway, the system comprising: one or more reference devices positioned along the roadway, each of the reference devices further comprising: a memory device for storing fixed values for one or more vehicle and traffic related parameters; and one or more transmission modules for transmitting said fixed values for one or more vehicle and traffic related parameters; a vehicle mounted device comprising: a receiving module for receiving transmitted signals from the transmission module of said reference devices; and a processing module for processing the received signals and a transmitter module to transmitting signals to the reference device to communicate with one or more controllers of the vehicle to guide and control movement of the vehicle along the roadway.

A vehicle power supply system, being mounted on a vehicle, includes: a main power supply system including a main low-voltage power supply and a normal load; and a backup power supply system including a backup low-voltage power supply and an emergency important load and connected to the main power supply system. A backup power supply control device of the backup power supply system is configured to execute a backup low-voltage power supply state estimation processing, and output a signal indicating that the backup low-voltage power supply is in a state allowing supplying electric power for operating the emergency important load based on an estimation result of the backup low-voltage power supply state estimation processing, in a case in which the state of the vehicle does not satisfy a predetermined condition.

A vehicle power supply system, being mounted on a vehicle, includes: a main power supply system including a main low-voltage power supply and a normal load; and a backup power supply system including a backup low-voltage power supply and an emergency important load and connected to the main power supply system. A backup power supply control device of the backup power supply system is configured to execute a backup low-voltage power supply state estimation processing, and output a signal indicating that the backup low-voltage power supply is in a state allowing supplying electric power for operating the emergency important load based on an estimation result of the backup low-voltage power supply state estimation processing, in a case in which the state of the vehicle does not satisfy a predetermined condition.

A drive system comprises a DC-DC converter that is arranged to receive an input voltage from a battery having a nominal battery voltage. The DC-DC converter has a first mode of operation in which the DC-DC converter generates a regulated output voltage from the input voltage and supplies the regulated output voltage to a load, and a second mode of operation in which the DC-DC converter is by-passed such that the input voltage from the battery is supplied to the load. A controller is arranged to compare the input voltage to a threshold voltage that is less than the nominal battery voltage. The controller operates the DC-DC converter in the first mode when the input voltage is less than the threshold voltage, and operates the DC-DC converter otherwise.

A drive system comprises a DC-DC converter that is arranged to receive an input voltage from a battery having a nominal battery voltage. The DC-DC converter has a first mode of operation in which the DC-DC converter generates a regulated output voltage from the input voltage and supplies the regulated output voltage to a load, and a second mode of operation in which the DC-DC converter is by-passed such that the input voltage from the battery is supplied to the load. A controller is arranged to compare the input voltage to a threshold voltage that is less than the nominal battery voltage. The controller operates the DC-DC converter in the first mode when the input voltage is less than the threshold voltage, and operates the DC-DC converter otherwise.

A vehicle underbody structure includes a pair of rockers that are provided on both vehicle width direction sides of a vehicle underbody and extend in a vehicle front-rear direction, a battery that is disposed centrally in a vehicle width direction center between the pair of rockers and is disposed above a vehicle floor and on the lower side of a seat, a fuel tank that is disposed in the vehicle width direction center between the pair of rockers and is disposed under the vehicle floor and further toward a rear side of the vehicle than the battery, and a waste pipe that is coupled to a drive unit provided at a vehicle front side of the battery and extends in the vehicle front-rear direction between the battery and one of the rockers.

An electrified tractor includes a vehicle body, a working machine, an electric motor, a battery, an inverter that controls input-output electric power of the battery. The electrified tractor includes a control device that controls the inverter. The control device executes a restriction process, a charging rate calculation process and a relaxation process. In the restriction process, the control device controls the inverter such that the input and output of the battery is restricted within a prescribed electric power range, when a state of the battery satisfies a restriction condition. In the charging rate calculation process, the control device calculates a charging rate of the battery when it is assumed that a work is finished in a farming field, as an estimated charging rate. In the relaxation process, the control device expands the prescribed electric power range, when the estimated charging rate is higher than a first prescribed charging rate.

An electrified tractor includes a vehicle body, a working machine, an electric motor, a battery, an inverter that controls input-output electric power of the battery. The electrified tractor includes a control device that controls the inverter. The control device executes a restriction process, a charging rate calculation process and a relaxation process. In the restriction process, the control device controls the inverter such that the input and output of the battery is restricted within a prescribed electric power range, when a state of the battery satisfies a restriction condition. In the charging rate calculation process, the control device calculates a charging rate of the battery when it is assumed that a work is finished in a farming field, as an estimated charging rate. In the relaxation process, the control device expands the prescribed electric power range, when the estimated charging rate is higher than a first prescribed charging rate.