Welding Inverter Restriking Circuit for High-Frequency Arc Stability
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Solution Overview
Problem
Conventional AC arc welding power supply devices face challenges in suppressing arc breaks when the polarity switching frequency of the output current is high, due to insufficient charging time for restriking voltage, leading to energy shortages and arc break occurrences.
Innovation Solution
A welding power supply device with an inverter circuit and a voltage superimposing circuit that includes a restriking capacitor, a charging circuit with a DC power supply and voltage booster, and a discharging circuit, allowing for rapid charging of the restriking capacitor by switching between direct and boosted voltage application states to ensure quick charging even at high polarity switching frequencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the polarity switching frequency of output current is increased, then welding productivity is improved, but the charging time for restriking voltage becomes insufficient causing arc breaks
Solution Approach 1:
The charging circuit performs preliminary charging of the restriking capacitor during the AC cycle when voltage and current are in phase, before the polarity switching occurs. This advance charging ensures that sufficient energy is stored in the capacitor prior to the restriking moment, eliminating the time conflict between high-frequency switching and capacitor charging requirements.
Solution Approach 2:
The charging circuit dynamically adjusts its operation based on the instantaneous voltage and current phases. By detecting when voltage and current are in phase, the circuit activates charging mode, and switches to standby mode when they are out of phase, optimizing the charging timing to match the dynamic requirements of high-frequency AC welding.
2Device complexity
If conventional charging circuits are used, then device complexity is low, but arc stability deteriorates at high polarity switching frequencies
Solution Approach 1:
The charging circuit incorporates feedback mechanisms that monitor the instantaneous voltage and current phases. Based on this feedback, the circuit intelligently determines when to activate charging mode versus standby mode, ensuring precise timing control that maintains arc stability even at high polarity switching frequencies without requiring complex additional hardware.
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 configuration effectively suppresses arc breaks by shortening the charging time of the restriking capacitor, ensuring sufficient energy for restriking and maintaining arc stability even at high polarity switching frequencies.
Implementation Method 1
a voltage booster that boosts a DC voltage of the DC power supply
Implementation Method 2
a restriking capacitor to be charged with the restriking voltage
Data Source
AI summary
A welding power supply device includes an inverter for converting DC power into AC power outputted to a welding load, and a voltage circuit for superimposing a restriking voltage on an output to the welding load when the polarity of output current of the inverter switches. The voltage circuit includes a restriking capacitor charged with the re-striking voltage, a charging circuit to charge the capacitor with the restriking voltage, and a discharging circuit to discharge the voltage in the capacitor. The charging circuit includes a DC power supply and a booster to boost DC voltage from the DC power supply. The charging circuit charges the restriking capacitor in first and second states. In the first state, the DC voltage from the DC power supply is directly applied to the re-striking capacitor. In the second state, DC voltage boosted by the booster is applied to the restriking capacitor.