Horsepower control system of a hybrid excavator and control method therefor

Abstract

Disclosed are a horsepower control system for a hybrid excavator and a control method thereof which controls the driving of a generator driver or a swing motor driver with a swing power ratio of 1 and a hydraulic power ratio of 1 in a first operation mode, and with a swing power ratio of r (a user set value) and a hydraulic power ratio of 1−r in a second operation mode. When the power required by the user is fully used, energy from an energy storage is used to maximize work capacity. When the total horsepower used is limited to the range of horsepower available, the limited use of the driving device is at a level of horsepower similar to that of a typical system, thereby minimizing fuel consumption.

1 . A horsepower control system for a hybrid excavator, comprising:
 an engine;   a hydraulic pump configured to be driven by the engine to drive a hydraulic actuator by hydraulic fluid;   a generator configured to be driven by the engine to generate electric energy;   an energy storage device configured to charge the electric energy generated from the generator and supply the electric energy to an swing electric motor; and   a power controller configured to control the driving operation of a generator driver or a swing motor driver with a swing power ratio of 1 (or 100%) and a hydraulic horsepower ratio of 1 using both the power of the energy storage device and the horsepower of the engine when a first operation mode according to a user setting is selected, thereby maximizing the operation amount of the excavator, and configured to control the driving operation of the generator driver or the swing motor driver with a swing power ratio of r (i.e., a user set value) and a hydraulic horsepower ratio of 1−r using either the power of the energy storage device or the horsepower of the engine when a second operation mode according to a user setting is selected, thereby minimizing fuel consumption through the limitation of the horsepower.   
     
     
         2 . The horsepower control system according to  claim 1 , wherein the energy storage device is either a battery or a super capacitor capable of storing the electric energy, or an accumulator capable of storing hydraulic energy. 
     
     
         3 . A horsepower control method of a horsepower control system for a hybrid excavator including an engine, a hydraulic pump configured to be driven by the engine to drive a hydraulic actuator by hydraulic fluid, a generator configured to be driven by the engine to generate electric energy, and an energy storage device configured to charge the electric energy generated from the generator and supply the electric energy to an swing electric motor, the horsepower control method comprising the steps of:
 controlling the driving operation of a generator driver or a swing motor driver with a swing power ratio of (or 100%) and a hydraulic horsepower ratio of 1 (or 100%) using both the power of the energy storage device and the horsepower of the engine when a first operation mode according to a user setting is selected, thereby maximizing the operation amount of the excavator; and   controlling the driving operation of the generator driver or the swing motor driver with a swing power ratio of r (i.e., a user set value) and a hydraulic horsepower ratio of 1−r using either the power of the energy storage device or the horsepower of the engine when a second operation mode according to a user setting is selected, thereby minimizing fuel consumption through the limitation of the horsepower.