Arc Welding Circuit Inductance Sensing for Real-Time Resistance Tracking
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Solution Overview
Problem
Welding power supplies face challenges in accurately determining welding conditions at a workpiece remotely due to long welding cables, which increase circuit inductance and impedance, making it difficult to obtain reliable feedback measurements without dedicated sense leads, and introducing noise in communication.
Innovation Solution
A welding power supply system that includes output circuitry, current and voltage sensors, and a controller to monitor and control welding waveforms, determining circuit inductance and electrode resistance in real time, allowing for accurate feedback without dedicated sense leads by using voltage and current measurements during controlled current changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If long welding cables are used to extend the welding circuit, then the workpiece can be positioned remotely, but the circuit inductance and impedance increase significantly, degrading measurement accuracy and control performance
Solution Approach 1:
The system uses real-time feedback from voltage and current sensors to continuously monitor welding conditions and detect short circuit events. The controller processes this feedback data to determine when short circuits occur and when they clear, enabling accurate measurement despite long cable inductance.
Solution Approach 2:
The welding power supply system monitors its own operating conditions using built-in voltage and current sensors. The controller analyzes the voltage and current waveforms to self-diagnose short circuit events and clear conditions without requiring external measurement equipment, eliminating the need for dedicated sense leads.
2Measurement precision
If dedicated sense leads are used to make remote feedback measurements, then measurement accuracy improves, but system complexity and cost increase, and the sense leads become fragile and easily broken
Solution Approach 1:
The invention extracts the measurement function from separate dedicated sense leads and integrates it into the existing voltage and current sensing circuitry of the welding power supply. By utilizing the already-present sensors and their signal paths, the system eliminates the need for additional sense lead wiring while maintaining measurement capability.
Solution Approach 2:
The voltage and current sensors in the welding power supply serve multiple functions: they control the welding waveform and simultaneously detect short circuit events and clear conditions. This multi-functionality eliminates the need for dedicated sense leads, reducing system complexity while maintaining measurement accuracy.
3Device complexity
If feedback measurements are made over welding cables, then system complexity is reduced, but noise along the cables degrades the quality of communication and measurement data
Solution Approach 1:
The system converts the potentially harmful noise on welding cables into useful information by analyzing the voltage and current waveforms. The controller detects short circuit events and clear conditions by identifying specific waveform characteristics, turning noise-containing signals into reliable diagnostic data.
4Productivity
If the welding power supply controls complex welding waveforms with fast current changes, then welding performance improves, but accurate feedback measurements become more difficult due to inductance and impedance
Solution Approach 1:
The system uses periodic sampling of voltage and current waveforms to monitor welding conditions during complex welding operations. By continuously sampling the waveforms at regular intervals, the controller can detect short circuit events and clear conditions even during fast current changes, maintaining measurement accuracy while supporting high-performance welding.
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
Enables accurate real-time determination of welding conditions, including short circuit events and electrode stickout, reducing spatter and improving weld quality by adjusting welding parameters based on calculated circuit impedance and resistance, even with long welding cables.
Implementation Method 1
a current sensor for measuring a welding current generated by the output circuitry
Implementation Method 2
a voltage sensor for measuring an output voltage of the welding waveform
Implementation Method 3
The controller is configured to determine a circuit inductance from the output voltage and the controlled change in current
Implementation Method 4
determine a change in resistance of a consumable electrode in real time based on the circuit inductance
Data Source
AI summary
A welding or additive manufacturing power supply includes output circuitry configured to generate a welding waveform, a current sensor for measuring a welding current generated by the output circuitry, a voltage sensor for measuring an output voltage of the welding waveform, and a controller operatively connected to the output circuitry to control the welding waveform, and operatively connected to the current sensor and the voltage sensor to monitor the welding current and the output voltage. A portion of welding waveform includes a controlled change in current from a first level to a second level different from the first level. The controller is configured to determine a circuit inductance from the output voltage and the controlled change in current, and further determine a change in resistance of a consumable electrode in real time based on the circuit inductance.