Pulse Arc Welding Current Control Under High Inductance
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Solution Overview
Problem
Non-consumable electrode pulse arc welding methods fail to maintain a consistent average welding current value as the inductance of the conduction path increases and pulse frequency rises, leading to decreased current amplitude and deteriorated welding quality.
Innovation Solution
A control method that adjusts the peak and base current setting signals using a current slope factor G (0 < G < 1.0) to calculate and control the welding current, ensuring the average welding current remains consistent by dynamically adjusting the current slope based on the inductance value and pulse frequency of the conduction path.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the inductance value of the conduction path is increased and the pulse frequency is raised, then the welding speed and productivity are improved, but the current amplitude decreases and the average welding current value becomes unstable, leading to deterioration in welding quality
Solution Approach 1:
The control method uses feedback control to detect the actual welding current and compare it with the target average welding current value. Based on the detection result, the control system adjusts the peak current and base current to maintain the average welding current at the desired level, even when inductance or pulse frequency changes. This closed-loop feedback mechanism resolves the contradiction by automatically compensating for current amplitude variations caused by high pulse frequency or increased inductance.
Solution Approach 2:
The control method dynamically changes the parameters of peak current and base current based on the detected average welding current value. When the average current deviates from the target, the system adjusts the magnitude and duration of peak and base current periods to restore the average current to the desired level. This parameter adjustment allows the system to maintain welding quality while operating at high pulse frequencies or with varied inductance values.
2Productivity
If the pulse frequency is increased to approximately 100 Hz or higher, then the welding efficiency is improved, but the peak current and base current amplitude become restricted and can no longer be conducted effectively
Solution Approach 1:
The control method dynamically adjusts the peak current and base current parameters in real-time based on the detected average welding current value. Instead of using fixed current amplitudes, the system continuously adapts the current waveform characteristics to maintain reliable conduction at high pulse frequencies. This dynamic adaptation ensures that even at 100 Hz or higher, the current amplitude remains sufficient for effective welding while maintaining the desired average current level.
Solution Approach 2:
The system employs feedback control to monitor the actual welding current and automatically adjust the peak and base current settings. This feedback mechanism ensures that the current conduction remains reliable by detecting any degradation in current amplitude and compensating through parameter adjustment, thereby maintaining effective welding current conduction even at high pulse frequencies where conventional fixed-parameter methods would fail.
3Speed
If the average welding current value is reduced due to increased inductance and high pulse frequency, then the system operates at higher frequencies, but the penetration depth and bead appearance deteriorate
Solution Approach 1:
The control method changes the parameters of peak current amplitude and base current amplitude based on the detected average welding current value. When operating at high pulse frequencies or with increased inductance, the system adjusts these parameters to maintain the average welding current at the desired level, ensuring adequate penetration depth and proper bead appearance while still benefiting from the higher pulse frequency operation.
Solution Approach 2:
The feedback control mechanism continuously monitors the average welding current and adjusts the peak and base current parameters to maintain the desired average current level. This ensures that even when operating at high pulse frequencies or with varied inductance, the penetration depth and bead appearance remain within acceptable quality ranges by preventing average current reduction that would otherwise occur with conventional control methods.
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 maintains the preset average welding current value even at high pulse frequencies and increased inductance, enhancing welding quality by stabilizing the current amplitude and penetration depth.
Implementation Method 1
the welding current changes at a slower speed as the inductance value of the conduction path increases
Implementation Method 2
non-consumable electrode arc welding includes direct current (DC) or alternating current (AC) TIG (Tungsten Inert Gas) welding and DC or AC plasma arc welding
Data Source
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Figure 2
AI summary
A non-consumable electrode pulse arc welding control method is provided for welding by conducting a welding current made up a peak current during a peak period and a base current during a base period. By the method, a peak current setting signal Ipr, a base current setting signal Ibr, and a current slope factor G (0 < G < 1.0) are set. The welding current is detected and a current detection signal Id is outputted. During the peak period, a first current setting signal is calculated based on a formula (Ipr-Id)×G+Id every control cycle, and the welding current is controlled based on the calculated first current setting signal. During the base period, a second current setting signal is calculated based on a formula (Ibr-Id)×G+Id every control cycle, and the welding current is controlled based on the calculated second current setting signal.