Electric driven hydraulic power system
The present invention relates to an electric driven hydraulic power system for heavy equipment, and more particularly, to a hydraulic power system, which includes a hydraulic pump operated by a battery and a motor, a supply line for supplying a hydraulic oil that is supplied by the hydraulic pump, a plurality of actuators, and a controller for controlling the motor and the actuators, in which electrical efficiency is significantly improved. In particular, the present invention relates to an electric driven hydraulic power system in which a plurality of motors and a plurality of hydraulic pumps corresponding to the motors, respectively, are provided, and a main control valve (MCV) for receiving a hydraulic oil from the hydraulic pumps to supply the hydraulic oil to a plurality of actuators is provided, so that efficient control is performed according to an operating load, an operating temperature, a supply flow rate, and the like to minimize power consumption of the motor, and thus electrical efficiency is improved to dramatically increase an operating time.
1. An improved electric driven hydraulic power system including a plurality of hydraulic actuators, which are first to kth hydraulic actuators (A1 to AK), the electric driven hydraulic power system comprising:
a first motor (M1), a second motor (M2), . . . , and an nth motor (Mn), which are a plurality of motors, and a first inverter (I1), a second inverter (I2), . . . , and an nth inverter (In) connected to the motors to convert a direct current of a battery into alternating currents and to convert rotation speeds of the motors, respectively;
a first hydraulic pump (P1), a second hydraulic pump (P2), . . . , and an nth hydraulic pump (Pn), which are a plurality of hydraulic pumps directly connected to shafts of the motors to supply a hydraulic oil introduced from a storage tank to a main control valve (MCV), respectively;
the main control valve (MCV) including a plurality of control valves, which are first to jth control valves (V1 to Vj) provided inside the main control valve (MCV) to convert a flow path of the hydraulic oil so as to receive the hydraulic oil supplied from the first to nth hydraulic pumps (P 1 to Pn) and selectively supply the hydraulic oil or block the supply of the hydraulic oil to the first to kth hydraulic actuators (A1 to Ak);
the hydraulic actuators, which are the first to kth hydraulic actuators (A1 to AK) for receiving the hydraulic oil of the main control valve (MCV) to perform predetermined operations;
a control unit ( 100 ) for individually controlling each of the first to nth inverters (I1 to In), each of the first to nth motors (M1 to Mn), and the control valves, which are the first to jth control valves (V1 to Vj) provided inside the main control valve (MCV);
a storage tank ( 400 ) for supplying the hydraulic oil to the first to nth hydraulic pumps (P1 to Pn), and accommodating the hydraulic oil returned from the main control valve (MCV);
a battery for supplying a current to the first to nth motors (M1 to Mn), the main control valve (MCV), and the control unit; and
a battery management system (BMS) for controlling and managing the battery, wherein first to nth discharge pipes (L1 to Ln) are connected to outlets of the first to nth hydraulic pumps (P1 to Pn), respectively, the discharge pipes are integrated into one supply pipe (L 100 ), and the supply pipe (L 100 ) is connected to an inlet of the main control valve (MCV), and
wherein a hydraulic pump and a motor among the first to nth motors (M1 to Mn) are selected and driven in consideration of a required flow rate of the hydraulic oil, in which when the selected motor is already overheated, the selected motor is not driven, and a hydraulic pump having a second-largest capacity and a motor are selected to be driven.
2. The electric driven hydraulic power system of claim 1 , wherein the first to nth hydraulic pumps (P1 to Pn) are configured as a plurality of hydraulic pumps having mutually different capacities, in which the control unit ( 100 ) first operates one hydraulic pump to maintain a constant hydraulic pressure and sequentially operates another hydraulic pump after a predetermined time so as to reduce power consumption.
3. An improved electric driven hydraulic power system including a plurality of hydraulic actuators, which are first to kth hydraulic actuators (A1 to AK), the electric driven hydraulic power system comprising:
a first motor (M1), a second motor (M2) , . . . , and an nth motor (Mn), which are a plurality of motors, and a first inverter (I1), a second inverter (I2), . . . , and an nth inverter (In) connected to the motors to convert a direct current of a battery into alternating currents and to convert rotation speeds of the motors, respectively;
a first hydraulic pump (P1), a second hydraulic pump (P2), . . . , and an nth hydraulic pump (Pn), which are a plurality of hydraulic pumps directly connected to shafts of the motors to supply a hydraulic oil introduced from a storage tank to a main control valve (MCV), respectively;
the main control valve (MCV) including a plurality of control valves, which are first to jth control valves (V1 to Vj) provided inside the main control valve (MCV) to convert a flow path of the hydraulic oil so as to receive the hydraulic oil supplied from the first to nth hydraulic pumps (P1 to Pn) and selectively supply the hydraulic oil or block the supply of the hydraulic oil to the first to kth hydraulic actuators (A1 to Ak);
the hydraulic actuators, which are the first to kth hydraulic actuators (A1 to AK) for receiving the hydraulic oil of the main control valve (MCV) to perform predetermined operations;
a control unit ( 100 ) for individually controlling each of the first to nth inverters (I1 to In), each of the first to nth motors (M1 to Mn), and the control valves, which are the first to jth control valves (V1 to Vj) provided inside the main control valve (MCV);
a storage tank ( 400 ) for supplying the hydraulic oil to the first to nth hydraulic pumps (P1 to Pn), and accommodating the hydraulic oil returned from the main control valve (MCV);
a battery for supplying a current to the first to nth motors (M1 to Mn), the main control valve (MCV), and the control unit; and
a battery management system (BMS) for controlling and managing the battery,
wherein first to nth discharge pipes (L1 to Ln) are connected to outlets of the first to nth hydraulic pumps (P1 to Pn), respectively, the discharge pipes are integrated into one supply pipe (L 100 ), and the supply pipe (L 100 ) is connected to an inlet of the main control valve (MCV), wherein the control unit ( 100 ) selects and drives a hydraulic pump among the hydraulic pumps based on a total amount of the hydraulic oil required to operate one or more of the first to kth hydraulic actuators (A1 to AK), in which the control unit ( 100 ) performs a control to first drive a hydraulic pump having a small capacity to discharge the hydraulic oil having a required flow rate.
4. The electric driven hydraulic power system of claim 3 , wherein the first to nth hydraulic pumps (P1 to Pn) are configured as a plurality of hydraulic pumps having mutually different capacities, in which the control unit ( 100 ) first operates one hydraulic pump to maintain a constant hydraulic pressure and sequentially operates another hydraulic pump after a predetermined time so as to reduce power consumption.