Welding Circuit Coupling Detection for Arc Stability Compensation

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Solution Overview

Problem

The existing welding systems face challenges in determining and minimizing interfering coupling between welding current circuits, which affects the welding process due to induced voltages and currents, leading to fluctuations in arc length and quality, especially when pulse frequencies differ.

Innovation Solution

A method is introduced to determine interfering coupling by applying a specified current profile in one welding circuit and measuring the voltage and current profiles in another, allowing for the calculation of ohmic and inductive coupling factors, which are then used to calculate a compensation voltage to correct the measurement voltage and regulate the welding current.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If multiple welding circuits are operated simultaneously in a welding system, then productivity is improved through parallel welding operations, but interfering coupling between circuits causes arc length fluctuations and quality deterioration

Engineering Contradiction:
Improveparallel welding operationsVSAvoidwelding quality consistency
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent implements a feedback mechanism where the actual welding current is continuously measured and compared with the reference current. The difference (deviation) is detected and used to generate a compensation signal that is fed back to the power source to correct the interfering coupling effects in real-time, thereby maintaining welding quality consistency during parallel operations

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent introduces an intermediary compensation circuit that includes a compensating power source and measurement devices. This intermediary system detects the interfering coupling between welding circuits and generates compensating signals to counteract the harmful effects, acting as a mediator between the conflicting welding circuits

Inventive Principle:
Principle #24Intermediary (Mediator)

2Device complexity

If welding circuits are placed closer together to reduce space usage, then device complexity is reduced, but interfering coupling increases causing arc length fluctuations

Engineering Contradiction:
Improvecircuit arrangementVSAvoidinterfering coupling
Core Design Contradiction:
Device complexityVSObject-affected harmful factors

Solution Approach 1:

The feedback mechanism continuously monitors the welding current and detects interfering coupling effects regardless of circuit proximity. By comparing actual current with reference current and applying real-time compensation, the system can maintain stable welding parameters even when circuits are placed close together, eliminating the need for complex spatial separation

Inventive Principle:
Principle #23Feedback

3Adaptability or versatility

If pulse frequencies of different welding circuits are not synchronized, then adaptability is improved for different welding tasks, but interfering coupling causes beats and arc length fluctuations

Engineering Contradiction:
Improvepulse frequency variationVSAvoidarc length fluctuations
Core Design Contradiction:
Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The feedback system detects current deviations caused by interfering coupling between circuits with different pulse frequencies. The compensation signal generated based on the current difference adapts dynamically to counteract the beats and arc length fluctuations, allowing different pulse frequencies to coexist without compromising welding stability

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent employs parameter changes by dynamically adjusting the compensation signal parameters (amplitude and frequency) based on the detected interfering coupling characteristics. This allows the compensation mechanism to adapt to varying pulse frequencies and coupling conditions, maintaining welding quality across different operational scenarios

Inventive Principle:
Principle #35Parameter changes

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

This method effectively reduces mutual interference between welding current sources, improving the consistency and quality of the welding process by compensating for induced voltages and currents, thereby enhancing the weld seam quality.

Implementation Method 1

Each of the welding circuits has a welding power source (4-1, 4-2) that generates a welding current (I) for welding the workpiece (3)

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Implementation Method 2

The welding circuit inductance L of the welding circuit SSK is understood to mean the property of the welding circuit to counter any change in current with a dynamic resistance

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 3

As soon as the current has reached the pulse current value I p (t 3 ), the wire end of the welding wire electrode is severely melted and a drop forms. This is constricted by the magnetic pinch effect

Methodology Applied
Scientific EffectMagnetic constriction: Magnetic Field

Data Source

PatentEP3843931B1Method for determining an interfering coupling between welding current circuits of a welding installation
Publication Date: 2022.10.05 FRONIUS INT GMBH
  • EP3843931B1 patent drawingFigure 1~2
  • EP3843931B1 patent drawingFigure 3~4
  • EP3843931B1 patent drawingFigure 5~6

AI summary

The invention relates to a method for determining an interfering coupling between welding circuits (2-i) of a welding system (1), comprising the following steps: applying (S1) a predefined current profile (SP) in a first welding circuit (2-1) of the welding system (1); sensing (S2) a voltage curve and/or current curve coupled thereby into a second welding circuit (2-2) of the welding system (1); and determining (S3) the interfering coupling on the basis of the current profile (SP) of the current applied in the first welding circuit (2-1) and the voltage curve and/or current curve sensed in the second welding circuit (2-2).