Compensation Voltage Control for Coupled Welding Current Circuits

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Solution Overview

Problem

The existing welding systems face interference between welding current circuits due to induced voltages, affecting the welding process, especially when multiple power sources are used simultaneously, and conventional methods to minimize this interference are often impractical or ineffective.

Innovation Solution

A method that calculates a compensation voltage based on the current profile of another welding power source, using stored coupling factors, to adjust the measurement voltage and control the welding current, thereby reducing or eliminating the interfering influence between welding circuits.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If multiple welding power sources are used simultaneously to increase productivity, then welding throughput is improved, but interference between welding circuits occurs due to induced voltages affecting measurement accuracy

Engineering Contradiction:
Improvewelding throughputVSAvoidmeasurement voltage accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The patent implements feedback by continuously monitoring the measurement voltage at the receiver welding power source and comparing it against expected values. When interference from another welding power source is detected, the system uses the determined coupling factor to calculate and apply a compensation voltage, creating a closed-loop control system that maintains measurement accuracy despite multiple simultaneous welding operations

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent introduces an intermediary compensation mechanism by determining a coupling factor that characterizes the interference relationship between welding circuits. This coupling factor serves as an intermediary parameter that enables the calculation of compensation voltage, acting as a mediator between the interfering welding sources and the affected measurement system

Inventive Principle:
Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If conventional methods are used to minimize interference by spatial separation of welding circuits, then interference is reduced, but device complexity and installation difficulty increase

Engineering Contradiction:
Improveinterference levelVSAvoidcircuit layout complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent changes the approach from spatial parameter optimization (physical separation of circuits) to electrical parameter compensation (adjusting voltage parameters). By determining a coupling factor and applying compensation voltage, the system transforms the problem from one requiring complex physical layout optimization to one solved through electrical parameter adjustment, simplifying the overall system complexity

Inventive Principle:
Principle #35Parameter changes

3Area of stationary object

If welding circuits are routed close together to save space, then space utilization is improved, but coupling between circuits increases causing measurement errors

Engineering Contradiction:
Improvewelding system footprintVSAvoidvoltage measurement accuracy
Core Design Contradiction:
Area of stationary objectVSMeasurement precision

Solution Approach 1:

The patent converts the harmful effect of close circuit routing (increased coupling and interference) into a beneficial situation by using the determined coupling factor to calculate precise compensation voltage. The very proximity that causes interference also creates a predictable coupling relationship that can be quantified and compensated, transforming the problem into a solvable calculation

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

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 approach effectively reduces mutual interference between welding current sources, improving the consistency and quality of the welding process by compensating for the interfering coupling, allowing for better control of the welding current and enhancing the weld seam quality.

Implementation Method 1

Each of the welding circuits has a welding power source that provides a welding current for welding the workpiece. The welding power sources supply current in the welding circuit to a consumable welding wire electrode, with an arc being formed between the tip of the welding wire electrode and the surface of the workpiece. The welding wire electrode is melted by the arc

Methodology Applied
Scientific EffectArc heating: Electric Arc

Implementation Method 2

As soon as the current has reached the pulsed current value l 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. The current is then reduced to a lower current value (t 4 ), whereby the drop formed is further constricted and accelerated in the direction of the molten pool.

Methodology Applied
Scientific EffectMagnetic constriction: Lorentz Force

Data Source

PatentEP3843930B1Method for compensating for interference of a welding current from another welding current source
Publication Date: 2022.10.05 FRONIUS INT GMBH
  • EP3843930B1 patent drawingFigure 1~2
  • EP3843930B1 patent drawingFigure 3~4
  • EP3843930B1 patent drawingFigure 5~6

AI summary

A method for compensating for a disturbing influence on a welding current, provided by a welding current source (4) for welding a workpiece (3), by another welding current source (4'), the method comprising the following steps: (d) providing (SA) a compensation voltage (UKomp), which is calculated on the basis of a welding current profile provided by the other welding current source (4'); (e) subtracting (SB) the compensation voltage (UKomp) from a measurement voltage (UMess) measured by a voltage-measuring unit (8) of the welding current source (4) in order to determine a corrected measurement voltage (U'Mess); and (f) controlling (SC) the welding current generated by the welding current source (4) according to the corrected measurement voltage (U'Mess)·