Variable Minimum Current Welding Controller
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Solution Overview
Problem
Traditional constant voltage (CV) welding controllers often extinguish the welding arc by reducing current levels during high voltage instances, which is undesirable in welding processes using self-shielded flux cored wires.
Innovation Solution
A CV welding process power supply with a controller that computes a varying minimum current level and generates a current command signal to maintain a constant voltage, including a current sensor and voltage sensor to detect short circuits and adjust the welding current in sub-millisecond time frames, using progressively aggressive gains to clear short circuits and prevent arc extinction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If traditional CV controllers ramp down current to accommodate high voltage, then constant voltage output is achieved, but the welding arc is extinguished
Solution Approach 1:
The patent applies dynamics by making the minimum current level adjustable and adaptive rather than fixed. The controller dynamically modifies the minimum current threshold based on welding conditions, allowing the system to maintain arc continuity during high voltage events while still providing voltage regulation. This is achieved through a configurable parameter that sets the floor for current reduction, preventing the arc from extinguishing even when voltage spikes occur.
2Power
If current is decreased to maintain constant voltage during high voltage instances, then voltage control is improved, but welding arc extinction occurs
Solution Approach 1:
The patent applies preliminary anti-action by pre-configuring a minimum current level that acts as a protective threshold before high voltage events can cause arc extinction. The controller is programmed with this minimum current parameter in advance, which preemptively prevents the current from dropping below the level that would extinguish the arc. This anticipatory measure counteracts the harmful effect of voltage-induced current reduction before it can damage the welding process.
3Stability of the object's composition
If standard CV control loops are used, then voltage regulation is achieved, but arc outages and wire stubbing occur during short circuits
Solution Approach 1:
The patent applies parameter changes by introducing a configurable minimum current parameter that fundamentally alters the control loop behavior during high voltage and short circuit conditions. Instead of allowing current to drop to zero or near-zero levels during voltage spikes, the minimum current parameter ensures the current remains above a threshold sufficient to maintain arc continuity. This parameter modification transforms the control characteristics to prevent arc outages and wire stubbing while preserving voltage regulation capability.
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 prevents arc outages and wire stubbing by maintaining a minimum current level, efficiently detecting and responding to short circuits, and improving the system's ability to manage high voltage events, ensuring consistent welding operations.
Implementation Method 1
A controller is configured to compute a varying minimum current level during a welding process, decrease a welding current based upon a computed voltage error, and generate a current command signal to minimize the computed voltage error
Implementation Method 2
A CV welding process power supply includes a current sensor configured to sense current of welding power supplied by the power supply to a welding process and a voltage sensor configured to sense voltage of the welding power
Implementation Method 3
The controller is further configured to compare the current command signal to the computed varying minimum current level and apply either the current command signal or the computed varying minimum current level for control of welding output based upon the comparison
Data Source
AI summary
A constant voltage (CV) welding process power supply including a controller that implements a variable minimum current is provided. The controller is configured to periodically compute a running current value during a welding operation. The controller is also configured to periodically compute a minimum current value based on a difference between the running current value and a preset offset value, wherein the preset offset value remains constant throughout the welding operation.