Plasma Arc Power Supply Multi-Unit Polarity Switching
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Solution Overview
Problem
The existing plasma arc power supplies for welding and cutting machines are complex and costly due to the need for a dedicated power supply for forming a pilot arc, which complicates the structure and increases the number of components.
Innovation Solution
A plasma arc power supply system using multiple direct current power supply units, where one unit forms a pilot arc and another unit transitions to form a main arc, eliminating the need for a dedicated pilot arc power supply by switching polarity and current distribution among the units.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a dedicated DC power supply for pilot arc is added to the main power supplies, then the pilot arc can be formed reliably, but the structure becomes complicated and cost increases
Solution Approach 1:
The patent applies multi-functionality by enabling one of the N DC power supply units to perform dual roles: forming the pilot arc between main electrode and nozzle electrode, and then transitioning to supply current for the main arc between main electrode and workpiece. This eliminates the need for a dedicated pilot arc power supply while maintaining reliable arc formation.
Solution Approach 2:
The patent merges the pilot arc power supply function with the main power supply units. By configuring one power supply unit to handle both pilot arc formation and main arc current supply, the system combines previously separate functions into a unified structure, reducing component count and simplifying the overall system.
2Reliability
If a dedicated DC power supply for pilot arc is added to the main power supplies, then the pilot arc can be formed reliably, but the cost of the entire plasma arc power supply increases
Solution Approach 1:
The patent applies multi-functionality by enabling one of the N DC power supply units to perform dual roles: forming the pilot arc between main electrode and nozzle electrode, and then transitioning to supply current for the main arc between main electrode and workpiece. This eliminates the need for a dedicated pilot arc power supply while maintaining reliable arc formation.
Solution Approach 2:
The patent merges the pilot arc power supply function with the main power supply units. By configuring one power supply unit to handle both pilot arc formation and main arc current supply, the system combines previously separate functions into a unified structure, reducing component count and simplifying the overall system.
3Power
If multiple DC power supply units are used in parallel for large output, then the power output capacity increases, but the control complexity increases
Solution Approach 1:
The patent applies dynamics by implementing a switchable configuration where power supply units can dynamically change their function. The first DC power supply unit transitions from pilot arc formation mode to main arc current supply mode based on operational stage, allowing the system to adapt its configuration rather than requiring complex simultaneous control of all units.
Solution Approach 2:
The patent segments the operation into distinct phases: pilot arc formation phase handled by the first power supply unit, and main arc supply phase where the same unit (along with others) provides current. This temporal segmentation simplifies control compared to simultaneous multi-function operation.
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 simplifies the structure, reduces costs, and ensures stable load current output even in small current regions while minimizing power consumption and pilot arc current loss.
Implementation Method 1
forming a pilot arc between a main electrode and a nozzle electrode of the plasma arc apparatus
Implementation Method 2
forming a main arc between the main electrode and the workpiece
Data Source
AI summary
A plasma arc power supply with a simple structure and its control method enable shifting from a pilot arc to a main arc. A plasma arc power supply used in a plasma arc apparatus that processes a workpiece by forming a pilot arc between a main electrode and a nozzle electrode and subsequently forming a main arc between the main electrode and the workpiece includes N direct current power supply units (N≧2) having negative terminals connected to the main electrode and positive terminals to the workpiece, and a switch between the fourth power supply unit and the workpiece. The fourth power supply unit is connected to cause the nozzle electrode to have an opposite polarity to the main electrode. When the switch is open, the fourth power supply unit supplies a small current between the main electrode and the nozzle electrode while forming a pilot arc between them.