ELECTRIC POWER SYSTEM FOR AN EXCAVATOR TO IMPROVE ENERGY CONSUMPTION EFFICIENCY AND WORKING PERFORMANCE

摘要

PURPOSE: An electric power system for an excavator is provided to improve the energy efficiency and working performance of an excavator, to improve the fuel efficiency of construction machinery, and to correspond to environmental changes including the enforcement of exhaust gas regulations.;CONSTITUTION: An electric power system for an excavator comprises an electric power storage part, an auxiliary engine generation part, a main electric motor part, a hydraulic system, a pivotal part, and a main controller. The electric power storage part is made of batteries. The auxiliary engine generation part includes an engine, an engine generator, and an engine generation inverter. The engine is used as a power source to assist the batteries. The engine generator generates electric power using the engine. The engine generation inverter controls the operation of the engine generator. The main electric motor part includes a main electric motor, a main electric motor inverter, and a hydraulic pump. The main electric motor is operated by the batteries or the engine generator. The main electric motor inverter controls the operation of the main electric motor. The hydraulic pump receives driving power from the main electric motor. The hydraulic system includes a hydraulic motor and a hydraulic cylinder. The hydraulic motor is operated by the hydraulic pump. The hydraulic cylinder operates a boom, an arm, and a bucket. The pivotal part includes a pivotal generator motor, a pivotal inverter, and an upper pivotal body. The pivotal generator motor is operated by an electric motor to operate a pivotal driving device or to function as a generator in regenerative braking. The pivotal inverter controls the operation of the pivotal generator motor. The upper pivotal body is operated by the pivotal generator motor. The main controller controls the main electric motor inverter, the engine generation inverter, and the pivotal inverter.;COPYRIGHT KIPO 2013;[Reference numerals] (AA) Pressure of the manipulation of a joystick; (BB) Amount of manipulation of a driver; (CC) Pressure of the discharge of a pump; (DD) Working load; (EE) Main controller; (FF) Calculation logic of a command value of rotation speed of a main motor; (GG) Logic to calculate a command value for controlling the load of a hydraulic oil pump; (HH) Output a rotation speed command; (II) Controller for a main motor; (JJ) Control the speed of the main motor; (KK) Output a command to control the load; (LL) Electronic pump controller; (MM) Pump torque control