Welding Power Converter AC Waveform Short Circuit Control
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Solution Overview
Problem
In electric arc welding, electrode negative state welding results in lower heat input and can cause arc instability and spatter when short circuits occur, leading to inefficiencies and the need for post-welding cleanup.
Innovation Solution
A welding power converter with a short circuit detection circuit that changes the polarity of the welding current from negative to positive to clear short circuits, reducing spatter by managing the current flow and arc re-ignition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If DC electrode negative waveform is used for welding, then heat input is reduced, but arc instability and spatter occur when short circuits happen
Solution Approach 1:
The welding power converter dynamically switches between DC electrode negative and AC waveforms based on real-time short circuit detection. During normal welding, DC electrode negative provides low heat input, but upon detecting a short circuit, the system transitions to AC waveform to clear the short, then returns to DC electrode negative for continued welding. This dynamic adaptation resolves the contradiction by maintaining arc stability during short circuits while preserving low heat input during normal operation.
Solution Approach 2:
The invention changes the electrical parameter (current waveform type) from DC electrode negative to AC when a short circuit is detected. This parameter change allows the system to clear short circuits effectively without sustaining the spatter and arc instability problems associated with clearing shorts in DC electrode negative mode, while maintaining the low heat input benefit of DC electrode negative during normal welding periods.
2Loss of time
If short circuit is cleared using negative polarity, then short is eliminated rapidly, but spatter is generated
Solution Approach 1:
Instead of clearing the short circuit using negative polarity as in conventional systems, the invention inverts the approach by using AC waveform to clear the short. This reversal of the clearing mechanism eliminates the spatter problem associated with negative polarity short clearing while maintaining rapid short elimination capability.
Solution Approach 2:
The invention converts the potentially harmful AC waveform (which would normally increase heat input and is less commonly used) into a beneficial tool for clearing short circuits. By using AC waveform specifically for short clearing rather than continuous welding, the system eliminates spatter without suffering from the drawbacks of AC welding, effectively turning a potential harm into a 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
The solution effectively reduces spatter and maintains welding efficiency by stabilizing the arc and controlling heat input during short circuit events, improving the consistency of the welding process.
Implementation Method 1
In electric arc welding, it is generally known that welding in an electrode negative state can result in a lower overall heat input during a welding operation.
Implementation Method 2
an AC welding module which changes the polarity of the current of the DC electrode negative waveform from negative to positive after the detection of the short circuit event
Data Source
AI summary
A welder power supply and welding method are provided which utilizes a short arc welding method in which the waveforms have a positive polarity portion and negative portion to optimize heat input and provide heat and current control.