Hybrid excavator and method of controlling hybrid excavator

摘要

A motor generator control unit controls operation of a motor generator which generates power using a driving force transmitted from an engine. A charge/discharge control unit electrically connects first and second electrical power storage devices and controls charging/discharging of power between the first and second electrical power storage devices in response to an externally supplied control signal. A motor which is electrically connected to the second electrical power storage device is capable of regenerating electric energy and storing the regenerated energy in the second electrical power storage device. A control device supplies a control signal to at least one of the motor generator control unit and the charge/discharge control unit and reduces an electrical power storage target value of at least one of the first and second electrical power storage devices before the motor regenerates energy.

主权项

1. A hybrid excavator including a lower running body, an upper turning body which is turned on the lower running body, a boom having an end rotatably attached to the upper turning body, an arm having an end rotatably attached to the other end of the boom, and a work element rotatably attached to the other end of the arm,
the hybrid excavator comprising: an engine disposed in the upper turning body to generate a driving force; a motor generator disposed in the upper turning body to perform an electric power generating operation by the driving force transmitted from the engine; a motor generator control unit disposed in the upper turning body to control operation of the motor generator in response to an externally supplied control signal; a first electrical power storage device disposed in the upper turning body and being capable of storing electricity; a second electrical power storage device disposed in the upper turning body, electrically connected to the motor generator control unit and being capable of storing electricity; a charge/discharge control unit disposed in the upper turning body to electrically connect the first electrical power storage device and the second electrical power storage device together and control a charge/discharge operation between the first electrical power storage device and the second electrical power storage device in response to the externally supplied control signal; a motor disposed in the upper turning body and electrically connected to the second electrical power storage device, the motor being capable of performing a regeneration operation to generate electric energy from mechanical energy and capable of storing the electric energy generated by the regeneration operation in the second electrical power storage device; and a control device disposed in the upper turning body to supply a control signal to at least one of the motor generator control unit and the charge/discharge control unit, wherein the control device is arranged to reduce an electrical power storage target value of at least one of the first electrical power storage device and the second electrical power storage device before the regeneration operation is performed by the motor.