Method for performing energy-saving transformation on hydraulic press

Abstract

The invention relates to a method for performing energy-saving transformation on a hydraulic press. The technical problems are solved through the following technical scheme that: in the method for performing energy-saving transformation on the hydraulic press, a programmable logic controller (PLC) and a frequency converter are arranged on a control system of a hydraulic press; the PLC and the frequency converter are provided with communication interfaces; and during working circulation of a main oil cylinder of the hydraulic press, a motor is controlled to operate when requiring action and is controlled to stop when not requiring action, and frequency is changed when speed is required to change, so that the hydraulic press achieves the best energy-saving effect and the best speed control, electricity-saving rate is commonly between 30 and 80 percent and efficiency can be improved by 10 to 20 percent. According to the scheme, various hydraulic presses are subjected to energy-saving transformation by completely utilizing soft start and stop characteristics of the frequency converter, variable frequency characteristic, communication function and analog quantity function, so that better electricity-saving effect is achieved, and conditions of overload of the frequency converter and instability of the whole system are not generated easily.

Description

technical field [0001] The invention relates to the technical field of hydraulic machine control, in particular to a method for energy-saving transformation of a hydraulic machine. Background technique [0002] The development history of hydraulic presses has been more than 100 years; in the past 20 years, various countries in the world have developed various hydraulic presses such as forging manipulators and forging hydraulic press linkage units, large-scale die forging hydraulic presses, extrusion hydraulic presses, powder forming hydraulic presses, and pipe forming hydraulic presses. There have been many new developments; hydraulic presses are currently used in thermal power, steel, automobiles, home appliances, coal, cement building materials, petrochemicals, metallurgical mines, municipal water supply and other industries. [0003] At present, the general hydraulic machine uses the motor to control the oil pump, so that the oil pump rotates to generate a certain flow, a...

AI Technical Summary

Problems solved by technology

[0006] First of all, after the frequency conversion is installed, due to the poor overload capacity of the frequency converter, it is easy to cause the frequency converter to alarm and stop; in the previous frequency conversion transformation, this problem could not be solved well, because the output end of the piston rod of the main oil cylinder or its drive After the actuator touches the workpiece, the cavity in the oil cylinder cannot be enlarged, and the compression rate of the hydraulic oil is very small; at this time, the pressure rises very quickly when the oil output of the oil pump remains unchanged or changes little, and the flow rate The greater the local pressure (mainly the oil outlet), the higher the oil pump motor will be overloaded, the system will overflow with high pressure, and the oil temperature will rise

Although the variable pump has the problem of automatically adjusting the pressure and flow, it only triggers the action to change the flow after the pressure rises to a higher level. The adjustment action is relatively slow, which will also cause the inverter to alarm.

[0007] Secondly, the hydraulic system of the hydraulic machine often produces shock and vibration in actual use. The reasons are many and complicated. The characteristics of the solenoid valve, oil temperature, oil quality, pressure gauge or pressure relay failure will often lead to system instability.

[0008] Thirdly, the above-mentioned authorized patent adopts the common control of PLC programmable controller and PC host computer, the cost is higher and the control is more complicated

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