CN-115823041-B - Double-pump source hydraulic system

Abstract

The double-pump source hydraulic system comprises a driving module, a control module and an execution module, wherein the execution module comprises two load driving devices, the driving module comprises an oil tank, a constant delivery pump, an electrohydraulic proportional variable pump, a servo motor and a three-phase variable frequency synchronous motor, and the control module comprises a servo motor controller, a frequency converter and a reversing valve. The invention can be in an independent operation state of any load driving device, namely, the double-pump source hydraulic system is in a pressure control mode or a flow control mode, and simultaneously, when two load driving devices are simultaneously operated, namely, a constant delivery pump and an electro-hydraulic proportional pump are simultaneously operated, the control of the flow and the pressure of the pump outlet under different load change conditions is realized on the premise of smaller energy loss, and the stability of the system is effectively enhanced.

Inventors

• YANG JING
• Ren Guanxu
• QUAN LONG

Assignees

• 太原理工大学

Dates

Publication Date

20260508

Application Date

20221223

Claims (4)

1. 1. The utility model provides a dual pump source hydraulic system, it includes drive module, control module and execution module, execution module includes two load drive arrangement, two load drive arrangement is two hydraulic cylinder, or two hydraulic motor, or a hydraulic cylinder and a hydraulic motor's combination, its characterized in that: the driving module comprises an oil tank, a constant delivery pump (1), an electro-hydraulic proportional variable pump (2), a servo motor (3) and a three-phase variable frequency synchronous motor (4), wherein the oil tank comprises a first oil tank (11) and a second oil tank (12), an oil inlet of the constant delivery pump (1) is communicated with the first oil tank (11) through a pipeline, the servo motor (3) controls the oil outlet flow of the constant delivery pump (1) through controlling the rotating speed, the electro-hydraulic proportional variable pump (2) is a main pump source of a double-pump source hydraulic system, an oil inlet of the electro-hydraulic proportional variable pump (2) is communicated with the second oil tank (12) through a pipeline, the electro-hydraulic proportional variable pump (2) controls the oil outlet flow of the electro-hydraulic proportional variable pump (2) through changing the swinging angle, or the three-phase variable frequency synchronous motor (4) controls the oil outlet flow of the electro-hydraulic proportional variable pump (2) through controlling the rotating speed, and the displacement of the electro-hydraulic variable pump (1) and the rotating speed of the servo motor (3) are determined according to the leakage quantity of the electro-hydraulic variable pump (2) under different pressures; The control module comprises a servo motor controller (13), a controller (14), a frequency converter (15) and reversing valves (7 and 8), wherein a pipeline connected with an oil outlet of the constant delivery pump (1) is communicated with a pipeline connected with an oil outlet of the electro-hydraulic proportional variable pump (2) through an oil-way control main pipe, the oil-way control main pipe is respectively connected with two three-position four-way electro-hydraulic proportional reversing valves (7 and 8), and overflow valves (16, 17 and 24) are respectively arranged on the pipeline at the oil outlet side of the constant delivery pump (1), the pipeline at the oil outlet side of the electro-hydraulic proportional variable pump (2) and the oil-way control main pipe; when three-position four-way electro-hydraulic proportional reversing valves (7, 8) are in an initial state, the three-position four-way electro-hydraulic proportional reversing valves (7, 8) are located in the middle position, P ports of the three-position four-way electro-hydraulic proportional reversing valves (7, 8) are respectively communicated with an oil path control main pipe, A ports of the three-position four-way electro-hydraulic proportional reversing valves (7, 8) are respectively communicated with a rodless cavity of a load driving device, B ports of the three-position four-way electro-hydraulic proportional reversing valves (7, 8) are respectively communicated with a rod cavity of the load driving device, T ports of the three-position four-way electro-hydraulic proportional reversing valves (7, 8) are communicated with an oil supplementing tank, pressure sensors (18, 19, 20, 21) are respectively arranged on the positions of the P ports and the A ports of the four-way electro-hydraulic proportional reversing valves (7, 8), displacement sensors (22, 23) are respectively arranged on piston rods of the load driving device, the pressure sensors (18, 19, 20, 21) and the displacement sensors (22), 23 Are electrically connected with the controller (14); The servo motor controller (13) is electrically connected with the servo motor (3), the frequency converter (15) is electrically connected with the three-phase variable frequency synchronous motor (4), the controller (14) is electrically connected with the servo motor controller (13) and the frequency converter (15) respectively, the controller (14) receives displacement feedback signals from the displacement sensors (22, 23), then the controller (14) sends out control signals, the controller (14) controls the rotating speed of the servo motor (3) through the servo motor controller (13), the controller (14) controls the rotating speed of the three-phase variable frequency synchronous motor (4) through the frequency converter (15), and the controller (14) controls the valve opening of the three-position four-way electro-hydraulic proportional reversing valve (7, 8) and the swing angle of the electro-hydraulic proportional variable pump (2).
2. 2. A double pump source hydraulic system according to claim 1, characterized in that the speed range of the servo motor (3) is determined from the lowest speed and the nominal speed of the dosing pump (1).
3. 3. The dual pump hydraulic system of claim 1, wherein any one of the load driving devices is in an independent operating state: 1) When the motion speed of a piston rod of the load driving device in an operating state is smaller than 0.2m/s, the electro-hydraulic proportional variable pump (2) is unloaded, the constant displacement pump (1) is independently operated, and the double-pump source hydraulic system is in a pressure control mode: Firstly, setting a target differential pressure delta p for three-position four-way electro-hydraulic proportional reversing valves (7, 8) through a controller (14); Then, the flow required for reaching the target pressure difference value and supplementing the internal leakage of the system is calculated: ; Wherein Q is the flow required for reaching the target pressure difference value and supplementing the internal leakage of the system, C q is the flow coefficient, A 0 is the valve port flow area of the three-position four-way electro-hydraulic proportional reversing valve, deltap is the target pressure difference value, and ρ is the liquid density; calculating the rotating speed of the servo motor (3) according to the required flow Q, and controlling the rotating speed of the servo motor (3) through a servo motor controller (13) so as to enable the inlet-outlet pressure difference of the three-position four-way electro-hydraulic proportional reversing valve (7, 8) to reach a target value delta p; Finally, according to the real-time pressure difference of the inlet and the outlet of the valve, changing the opening of the valve ports of the three-position four-way electro-hydraulic proportional reversing valve (7, 8), stabilizing the flow passing through the three-position four-way electro-hydraulic proportional reversing valve (7, 8), and keeping the pressure difference of the inlet and the outlet of the three-position four-way electro-hydraulic proportional reversing valve (7, 8) within the range of +/-0.05 MPa of the target value; 2) When the movement speed of the piston rod of the load driving device in the running state is greater than or equal to 0.2m/s, the double-pump source hydraulic system is in a flow control mode: The three-position four-way electro-hydraulic proportional reversing valve (7, 8) is controlled to be completely opened through a controller (14), the swing angle of the electro-hydraulic proportional variable pump (2) is controlled through the controller (14) to control the displacement of the electro-hydraulic proportional variable pump (2), meanwhile, the rotating speed of the three-phase variable frequency synchronous motor (4) is controlled through a frequency converter (15), finally, the flow control of the electro-hydraulic proportional variable pump (2) is finally realized, in addition, in order to ensure that a double-pump source hydraulic system is quickly converted into a flow control mode from a pressure control mode, the inlet-outlet pressure difference of the three-position four-way electro-hydraulic proportional reversing valve (7, 8) is calculated to be +/-0.5 MPa through the controller (14), then the flow required for achieving the target pressure difference and partial supplement of the system is calculated, the rotating speed of the servo motor (3) is calculated according to the required flow, and the rotating speed of the servo motor (3) is regulated through a servo motor controller (13), so that the outlet pressure of the constant delivery pump (1) is controlled, and finally, the pressure difference between the inlet-outlet of the three-position four-way electro-hydraulic proportional reversing valve (7, 8) is kept within a target value +/-0.05 MPa.
4. 4. A dual pump source hydraulic system according to claim 1, wherein the constant displacement pump (1) and the electro-hydraulic proportional pump (2) are operated simultaneously when the two load driving devices are operated simultaneously: Firstly, determining the system pressure by the maximum load pressure, keeping the opening of the valve port of the three-position four-way electro-hydraulic proportional reversing valve in the same path of the maximum load pressure unchanged, setting the target pressure difference value of the inlet and the outlet of the three-position four-way electro-hydraulic proportional reversing valve, Then, calculating the flow of the three-position four-way electro-hydraulic proportional reversing valve passing through the same path of the maximum load pressure; Finally, the swing angle of the electro-hydraulic proportional variable pump (3) and the frequency of a frequency converter (15) are calculated, the swing angle of the electro-hydraulic proportional variable pump ((2)) is changed, the rotating speed of a three-phase variable frequency synchronous motor (4) is changed through the frequency converter (15), so that the outlet flow of the electro-hydraulic proportional variable pump (2) is changed, the outlet flow of the constant displacement pump (3) is calculated through the leakage quantity of the electro-hydraulic proportional variable pump (2) and the valve inlet-outlet target pressure difference value, so that the rotating speed of the servo motor (3) is calculated, in addition, the inlet-outlet pressure difference of a three-position four-way electro-hydraulic proportional reversing valve with the same path of small load pressure is calculated in real time through a controller (14), and the valve opening of the three-position four-way electro-hydraulic proportional reversing valve is changed to achieve the target flow value.

Description

Double-pump source hydraulic system Technical Field The invention belongs to the technical field of hydraulic control, and relates to a double-pump source hydraulic system. Background In some applications, the dynamic response speed change requirement on the system oil pressure change is small when the load type is different and the load movement speed is sometimes large, the required oil flow of the system is larger and the single load movement speed is sometimes small but the load change is fast and the dynamic response of the system is required to be fast. In the current pump valve cooperative control system, when a load moves rapidly, namely the system needs larger flow, the requirement on flow resolution is not high, the system is in a flow control mode, namely the flow is mainly regulated by a pump, a throttle valve port is fully opened, when the load moves slightly, namely the system needs to accurately regulate the flow, the flow is mainly regulated by the valve port opening, the pump is responsible for controlling the pressure difference between an inlet and an outlet of the valve to remain unchanged, the system is in a pressure control mode, but when the pump is switched from the flow control mode to the pressure control mode, the system can vibrate, and then the hydraulic control system capable of enhancing the stability of the system is needed when the control mode of the system is switched. Disclosure of Invention The invention mainly aims to overcome the defects in the prior art and provides a double-pump source hydraulic system. In order to achieve the aim of the invention, the invention adopts the following technical scheme: The utility model provides a dual pump source hydraulic system, it includes drive module, control module and execution module, execution module includes two load drive arrangement, two load drive arrangement is two hydraulic cylinder, or two hydraulic motor, or a hydraulic cylinder and a hydraulic motor's combination, wherein: The driving module comprises an oil tank, a constant delivery pump, an electro-hydraulic proportional variable pump, a servo motor and a three-phase variable frequency synchronous motor, wherein the oil tank comprises a first oil tank and a second oil tank, an oil inlet of the constant delivery pump is communicated with the first oil tank through a pipeline, the servo motor controls the flow rate of an oil outlet of the constant delivery pump through controlling the rotating speed, the electro-hydraulic proportional variable pump is a main pump source of a double-pump source hydraulic system, an oil inlet of the electro-hydraulic proportional variable pump is communicated with the second oil tank through a pipeline, the electro-hydraulic proportional variable pump controls the flow rate of the oil outlet of the electro-hydraulic proportional variable pump through changing the swinging angle, or the three-phase variable frequency synchronous motor controls the flow rate of the oil outlet of the electro-hydraulic proportional variable pump through controlling the rotating speed; The control module comprises a servo motor controller, a frequency converter and a reversing valve, wherein a pipeline connected with an oil outlet of a quantitative pump is communicated with a pipeline connected with an oil outlet of an electrohydraulic proportional variable pump through an oil way control main pipe, the oil way control main pipe is respectively connected with two three-position four-way electrohydraulic proportional reversing valves, overflow valves are respectively arranged on the pipeline on one side of the oil outlet of the quantitative pump, the pipeline on one side of the oil outlet of the electrohydraulic proportional variable pump and the oil way control main pipe, when the three-position four-way electrohydraulic proportional reversing valve is in an initial state, a three-position four-way electrohydraulic proportional reversing valve is in a middle position, a P port of the three-position four-way electrohydraulic proportional reversing valve is respectively communicated with the oil way control main pipe, a port A of the three-position four-way electrohydraulic proportional reversing valve is respectively communicated with a rod cavity of a load driving device, and a T port of the three-position four-way electrohydraulic proportional reversing valve is respectively communicated with an oil supplementing tank; The servo motor controller is electrically connected with the servo motor, the frequency converter is electrically connected with the three-phase variable frequency synchronous motor, the controller is electrically connected with the servo motor controller and the frequency converter respectively, the controller receives displacement feedback signals from the displacement sensor, then the controller sends out control signals, the controller controls the rotating speed of the servo motor through the servo motor controller, the controller cont