PID control
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I would like to ask everyone: can a plunger pump and branches 1 and 2 be subjected to PID constant-pressure control simultaneously? The plunger pump maintains a constant pressure of 20 Mpa, while the two branches maintain a constant pressure of 18 Mpa
PID constant pressure control can be carried out simultaneously. By setting the pressure target value for the plunger pump at 20 MPa, and the pressure target values for Branch 1 and Branch 2 at 18 MPa, a PID controller is used to adjust each pressure to reach the preset values. It should be noted that the design of the control system and the adjustment of its parameters must ensure the stability and accuracy of pressure control. .
Theoretically, it is possible, but in practical use, even a slight change in the load can affect other control systems, leading to significant control fluctuations.
It is recommended to add a buffer tank; PID control works well. If the liquid is clean and there is a buffer tank, solenoid valves can also be used. Here, our experienced microcontroller experts use solenoid valves to control the pressure in the cooling water pipes, but this pressure is quite low – much lower than yours. Stabilize the pressure by frequently switching the solenoid valve.
This post was last edited by pzhmotor on 2024-7-19 at 16:13; it is somewhat similar to PID pressure regulation using an air compressor with variable frequency control connected to an air supply branch pipe. It is necessary to verify that the maximum flow rates of branch pipe 1 and branch pipe 2 are less than the rated flow rate of the plunger pump ； To reduce the excessive adjustment range of the plunger pump when there are large variations in the flow rate in the branch pipes, a buffering device is installed at the inlet of the main pipe or the branch pipes (it is not clear whether pressure regulators have this function) ； The pressure is high, and the buffer tank is not easy to handle). For reference
A two-branched pipeline pressure control system, with the two systems being interconnected. The degree of correlation is related to the resistance between the outlet of the plunger pump and the pipeline branch point; the greater the resistance, the stronger the correlation. When the correlation is severe, neither system can remain stable. The solution is to minimize the resistance between the outlet of the plunger pump and the pipeline branching point, or to add a buffer tank at the pump’s outlet.
Typically, plunger pumps are equipped with a relief valve; when the pressure exceeds a certain value, the fluid flows back to the front of the pump.
The control scheme used in PID is not recommended; the principle of plunger pumps dictates that outlet throttling control is not a good approach. The backflow adjustment mentioned on floor 8 could be tried.
In front is the plunger pump, then it passes through a pressure regulator, and behind that the pressure is connected to the manual valve with an M on it? What is being controlled? Is it a stroke motor, an electric valve? The latter actuator needs to respond quickly; motors with slow response times are difficult to control.