Hitachi Construction Machinery Co., Ltd.

Hiroshi Utashiro

Akinori Kamiya

Satoru Kaneko

Takatoshi Ooki

Noritaka Ito

Noritaka Itou

Satoshi Sekino

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.

Work vehicle

To provide a technique for reliably acquiring a required braking power during travel and for efficiently using a regenerative power generated during braking. A work vehicle calculates a regenerative power outputted from an electric motor and a target hydraulic driving power for driving a hydraulic pump, supplies the regenerative power to the generator motor operating as a motor and makes the generator motor consume the regenerative power in a case where the regenerative power is equal to or smaller than the target hydraulic driving power, and supplies the regenerative power to the generator motor operating as the motor and makes an exhaust brake consume a power equivalent to a difference between the regenerative power and the target hydraulic driving power in a case where the regenerative power is larger than the target hydraulic driving power.

Growing community of inventors

Ibaraki, Japan

Hiroshi Utashiro