Control method of buried arc welding arc voltage feed back wire feeding and circuit

Abstract

A method for controlling the arc voltage feedback wire feeding of submerged arc welding and a circuit thereof belong to the field of welding device and are applied to the electric arc voltage feedback wire feeding of submerged arc welding. A control system consists of a control procedure 1 consisting of an outer-loop controller 1.1 and an inner-loop controller 1.2, a wire feeding motor procedure 2 and an electric arc area 3. The method is characterized by adopting double closed loop negative feedback control; the outer-loop is provided with the outer-loop controller 1.1; the input end of the outer-loop is connected with a reference signal Verf and an electric arc voltage feedback signal Vf output by the electric arc area 3. The inner-loop is provided with the inner-loop controller 1.2 which is a controller provided with a current type PWM control function. The outer-loop controller 1.1 is connected with one input end of the inner-loop controller 1.2; a current feedback signal If output by the wire feeding motor procedure 2 is connected with the other input end of the inner-loop controller 1.2. The wire feeding motor procedure 2 after carrying out power amplifying on the output signal of the controller 1.2 drives the wire feeding motor in the wire feeding procedure; the wire feeding motor feeds welding wires into the electric arc area 3. The method has the advantages of being relative simple and having a high control precision.

Description

technical field [0001] The technology belongs to the field of welding equipment, and is suitable for submerged arc welding arc voltage feedback wire feeding technology. Background technique [0002] In the submerged arc welding system, there is a burning arc between the front end of the welding wire and the workpiece. The end of the welding wire melts under the heat of the arc, and the molten iron transitions into the weld. As the welding wire melts, the wire feeder must continuously feed Welding wire, to keep the distance from the end of the welding wire to the workpiece basically unchanged, otherwise the quality of the weld will be damaged, and the arc will be extinguished in severe cases, destroying the stable welding process. Since the distance from the end of the welding wire to the workpiece is proportional to the arc voltage, the arc voltage is used as the sensor for measuring the arc length, and the wire feeder driven by the servo motor is used as the actuator. The ...

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Problems solved by technology

The current problem of this technology is: in this control system, the main disturbance to the control system is the transition of molten iron droplets that are continuously melted at the end of the welding wire to the weld seam. This process is called droplet transfer.

The droplet transfer will change the value of the arc voltage, which frequently interferes with the measurement of the distance from the end of the welding wire to the workpiece. In addition, the entire control system cannot be described by a mathematical model due to the existence of the arc

Due to these characteristics, some existing submerged arc welding controls are too complicated, such as using three closed-loop control methods, such as ZL200510023284.7; some are simple but have low control accuracy, and the closed-loop magnification of the regulator is below 10 times

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