Arc Welding Device Dynamic Short Circuit Current Control

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Solution Overview

Problem

Conventional arc welding control methods often result in unstable welding and excessive sputtering due to inappropriate short circuit current waveforms, leading to abnormal short circuits and insufficient heat input.

Innovation Solution

An arc welding device with a detection and adjustment unit that dynamically adjusts the increase rate of the short circuit current based on the length of the short circuit and arc generation periods, ensuring rapid opening of short circuits to maintain stability and prevent sputtering.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If the increase rate of short circuit current is set to a large value to rapidly open the short circuit, then the response speed improves, but sputtering occurs greatly and welding becomes unstable

Engineering Contradiction:
Improveresponse speedVSAvoidwelding stability
Core Design Contradiction:
SpeedVSReliability

Solution Approach 1:

The patent applies dynamics by making the short circuit current waveform dynamic rather than fixed. The control device changes the waveform parameters (increase rate, peak current value, or duration) based on real-time detection of welding state parameters such as arc generation period length, short circuit generation period length, welding current, or welding voltage. This allows the system to adapt the current increase rate to each specific welding condition, achieving rapid short circuit opening when needed while preventing excessive sputtering and instability in other conditions.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent implements parameter changes by modifying the short circuit current waveform parameters according to the detected welding state. Specifically, the control device adjusts one or more parameters including the increase rate of short circuit current, the peak current value, or the duration of the short circuit current pulse. This dynamic parameter adjustment resolves the contradiction by selecting appropriate parameter values for each welding condition, enabling fast response when stability is compromised while maintaining controlled current increase rates during stable welding to prevent sputtering.

Inventive Principle:
Principle #35Parameter changes

2Speed

If the increase rate of short circuit current is set to a large value in advance, then the response to unstable welding improves, but heat input becomes insufficient and abnormal short circuits occur

Engineering Contradiction:
Improveresponse speedVSAvoidheat input
Core Design Contradiction:
SpeedVSUse of energy by moving object

Solution Approach 1:

The patent resolves this contradiction through parameter changes by dynamically adjusting the short circuit current waveform parameters based on the actual welding state. Instead of using a fixed large increase rate, the control device detects welding parameters (arc generation period, short circuit generation period, welding current, or voltage) and adjusts the current waveform parameters accordingly. This ensures adequate heat input during normal welding while enabling rapid response when instability is detected.

Inventive Principle:
Principle #35Parameter changes

3Device complexity

If the welding current increase rate is constant every time, then the control method is simple, but the short circuit current waveform is inappropriate for the welding state and abnormal short circuits occur

Engineering Contradiction:
Improvecontrol complexityVSAvoidshort circuit opening reliability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent applies feedback by implementing a closed-loop control system where the control device detects welding state parameters (arc generation period length, short circuit generation period length, welding current, or welding voltage) and uses this feedback information to adjust the short circuit current waveform parameters. This feedback mechanism ensures that the current waveform is appropriate for each welding state, enabling reliable short circuit opening while maintaining reasonable control complexity through automated detection and adjustment.

Inventive Principle:
Principle #23Feedback

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The solution effectively prevents welding instability and reduces sputtering by adjusting the short circuit current increase rate according to the detected periods, ensuring stable arc formation and efficient heat input.

Implementation Method 1

The detection unit detects at least one of a length of a short circuit generation period of this time and a length of an arc generation period of this time

Methodology Applied
Scientific EffectElectrical measurement:

Implementation Method 2

The adjustment unit adjusts an increase rate of a short circuit current in a short circuit generation period of next time according to the length of the short circuit generation period detected by the detection unit

Methodology Applied
Scientific EffectElectrical current control:

Implementation Method 3

carries out welding while repeatedly generating a short circuit state and an arc state between a consumable electrode and a welding member

Methodology Applied
Scientific EffectElectric arc: Electric Arc

Data Source

PatentEP2436471B1Arc welding device and arc welding system
Publication Date: 2020.06.03 YASKAWA DENKI KK
  • EP2436471B1 patent drawingFigure 1~2
  • EP2436471B1 patent drawingFigure 3~4
  • EP2436471B1 patent drawing

AI summary

An arc welding device according to an embodiment carries out welding while repeatedly generating a short circuit state and an arc state between a consumable electrode (14) and a welding member (W). The arc welding device includes a detection unit (4) and an adjustment unit (4). The detection unit (4) detects at least one of a length of a short circuit generation period of this time and a length of an arc generation period of this time. The adjustment unit (4) adjusts an increase rate of a short circuit current in a short circuit generation period of next time according to at least one of the length of the short circuit generation period and the length of the arc generation period detected by the detection unit (4).