Pulse Arc Welding Current Control for Fast Parameter Convergence

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Solution Overview

Problem

Conventional pulse arc welding power supplies face challenges in achieving good transient response and stability during automatic correction of pulse parameters, particularly at high-speed welding, where short circuits are more likely to occur, leading to increased sputtering and prolonged convergence to optimal parameter values.

Innovation Solution

A pulse arc welding power supply comprising a power control circuit, short circuit occurrence timing detection circuit, total correction amount calculation circuit, and parameter correction circuit, which detects short circuits within each pulse period and adjusts pulse parameters based on cumulative correction amounts across multiple pulse periods to improve transient response and stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-generated harmful factors

If pulse parameters are automatically adjusted based on distribution of short circuit occurrence per unit time, then sputtering is reduced, but transient response is slow and convergence to optimal parameters takes long time

Engineering Contradiction:
ImprovesputteringVSAvoidconvergence time
Core Design Contradiction:
Object-generated harmful factorsVSLoss of time

Solution Approach 1:

The patent applies preliminary action by pre-establishing the relationship between short circuit occurrence timing and parameter correction amounts before actual welding begins. The correction amounts are predetermined for each pulse period based on expected short circuit patterns, allowing immediate correction without waiting for statistical distribution analysis to converge. This enables fast transient response while still achieving the goal of reducing sputtering through proactive parameter adjustment.

Inventive Principle:
Principle #10Preliminary action

2Productivity

If arc length is shortened by reducing welding voltage setting value, then welding speed can be increased, but short circuits occur more frequently and sputtering increases

Engineering Contradiction:
Improvewelding speedVSAvoidsputtering
Core Design Contradiction:
ProductivityVSObject-generated harmful factors

Solution Approach 1:

The patent implements feedback control by detecting the actual timing of short circuit occurrences during welding and using this information to dynamically adjust pulse parameters. When short circuits are detected, the system automatically modifies parameters such as peak current, base current, or pulse width to prevent excessive sputtering. This closed-loop feedback enables high-speed welding with shortened arc length while maintaining control over sputtering through real-time parameter correction based on actual short circuit behavior.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP3991900B1Pulse arc welding power supply
Publication Date: 2023.07.19 DAIHEN CORP
  • EP3991900B1 patent drawingFigure 1
  • EP3991900B1 patent drawingFigure 2~2(C)

AI summary

A pulse arc welding power supply includes a power control circuit, a short circuit occurrence timing detection circuit, a total correction amount calculation circuit and a parameter correction circuit. The total correction amount calculation circuit calculates the sum of correction amounts for a correction cycle including a predetermined number of pulse periods. The parameter correction circuit adjusts, based on the sum of correction amounts, a pulse parameter relating to the waveform of a welding current.