Higher-Order Welding Line Modeling for Arc Voltage Reconstruction
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Solution Overview
Problem
Conventional R/L line models used in welding processes fail to accurately reconstruct arc voltage due to electromagnetic interactions with conductive materials, leading to significant estimation errors that can negatively impact welding quality.
Innovation Solution
A welding line model with an order greater than one is used to estimate arc voltage, accounting for magnetic coupling with conductive components, allowing for more precise estimation by modeling the welding line as a transmission system with multiple energy storage devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional R/L line model with one energy storage device is used, then the device complexity is low, but the measurement precision of arc voltage deteriorates due to electromagnetic interactions with conductive materials
Solution Approach 1:
The welding line is segmented into multiple discrete sections, each modeled as a separate transmission line segment with its own inductance and resistance parameters. This segmentation allows the model to capture local electromagnetic interactions with conductive materials along the cable path, improving arc voltage estimation accuracy by accounting for distributed coupling effects that a single lumped R/L model cannot represent
Solution Approach 2:
The model transitions from a one-dimensional R/L representation to a multi-dimensional transmission line model that incorporates spatial distribution of electromagnetic parameters along the cable length. By adding the dimensional aspect of cable length and position-dependent coupling, the model captures electromagnetic interactions with conductive materials at different locations, resolving the accuracy issue while managing complexity through structured parameter organization
2Measurement precision
If the welding line model accounts for electromagnetic interactions with conductive materials, then the measurement precision improves, but the device complexity increases due to multiple energy storage devices
Solution Approach 1:
The model parameters (inductance L, resistance R, coupling coefficients) are made variable and position-dependent along the welding line rather than constant. This allows the model to adapt to changing electromagnetic interaction conditions at different cable positions near conductive materials, improving accuracy while the parameter variations are managed through systematic identification methods that prevent exponential complexity growth
Solution Approach 2:
The model incorporates feedback mechanisms where the estimated arc voltage is continuously refined by comparing model predictions with actual measurements and adjusting the electromagnetic coupling parameters accordingly. This feedback loop enables the model to adapt to specific welding configurations and conductive material arrangements, improving precision without requiring a complete redesign of the entire modeling framework for each scenario
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 provides a more accurate estimation of arc voltage, improving weld seam quality and enabling better regulation of welding processes, including wire feed speed and heat input determination.
Implementation Method 1
Due to the highly dynamic welding currents flowing through the welding cable (time-varying electrical currents with steep edges and high frequencies), electromagnetic interaction with such components can occur. The time-varying welding currents cause time-varying magnetic fields in the vicinity of the welding cable. It is well known that an electrically conductive body located in a changing magnetic field induces an electric field strength, which, due to the conductivity, directly leads to the generation of electric current densities in the body.
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
In order to improve the estimation of the arc voltage for use in a welding process, according to the invention the welding line (4) is modelled using a welding line model (13) as a transmission system with an order greater than one for estimating the arc voltage (ûLB), and the estimated value of the arc voltage (ûLB) is determined as the difference between the measurement voltage (uM) at the measurement point (19) and the determined line voltage drop (uS).