Weld Circuit Inductance Tracking for Remote Arc Voltage Sensing
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Solution Overview
Problem
Accurate measurement of arc voltage in welding and plasma cutting systems is challenging due to fluctuations caused by inductance and resistance in the system, particularly when measuring remotely from the welding/cutting arc, leading to inaccuracies and increased complexity.
Innovation Solution
A method and apparatus that compensates for voltage drops in the weld circuit by measuring current and voltage remotely, using inductance tracking to adjust compensation values dynamically, thereby improving the accuracy of arc voltage estimation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If arc voltage is measured remotely at the power supply, then measurement convenience is improved, but measurement precision deteriorates due to voltage drops caused by inductance and resistance
Solution Approach 1:
The system continuously monitors the weld current and uses this feedback to dynamically calculate and update the inductance compensation value. The controller adjusts the compensation based on the relationship between current changes and voltage drops, creating a closed-loop system that maintains accuracy despite remote measurement conditions.
Solution Approach 2:
The system changes the compensation parameters dynamically based on operating conditions. By monitoring weld current variations and their relationship to voltage drops, the system adjusts the inductance compensation value in real-time, transforming a static compensation approach into a dynamic one that adapts to changing welding parameters.
2Measurement precision
If additional sensors are added to measure arc voltage in close proximity to the arc, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The system uses the power supply's existing voltage and current sensors as intermediaries to indirectly determine arc voltage. Instead of placing sensors near the arc, the system uses remote measurements combined with circuit parameter analysis (inductance and resistance calculations) to derive the arc voltage, eliminating the need for additional proximity sensors.
Solution Approach 2:
The invention replaces the mechanical approach of physically placing voltage sensors near the arc with a computational method. By using mathematical relationships between measured voltage, current, and calculated inductance, the system substitutes physical sensor placement with algorithmic processing of remote measurements.
3Measurement precision
If inductance compensation is used to correct voltage measurements, then measurement precision is improved, but device complexity increases due to additional calculations
Solution Approach 1:
The system performs preliminary determination of circuit inductance characteristics during the welding process. By pre-calculating the inductance value based on initial current and voltage measurements, the system prepares the compensation parameter in advance, simplifying subsequent real-time corrections without requiring complex iterative calculations during critical welding moments.
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 precise control of the welding process by providing accurate arc voltage measurements, reducing system complexity and cost through real-time inductance tracking and compensation.
Implementation Method 1
A welding or cutting system includes a power supply to deliver a current through a weld circuit to a welding torch to create an arc on a workpiece
Data Source
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AI summary
A method is performed in a welding or cutting system, including a power supply (102) to deliver a current through a weld circuit to a welding torch to create an arc and a controller (104) coupled to the power supply. The method includes: measuring the current to produce a measured current; measuring a voltage on a sense point of the power supply or the weld circuit that is spaced from the welding torch, to produce a measured voltage that differs from the arc voltage by a voltage drop caused by the current and inductance of the weld circuit; compensating the measured voltage for the voltage drop using the measured current and an inductance value, to produce a compensated voltage; computing a derivative of the compensated voltage; computing a second derivative of the measured current; and upon determining the inductance value and the inductance differ based on the derivative and the second derivative, adjusting the inductance.