Welding Power Source AC Bypass for Lower DC Conduction Loss

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing welding power sources experience power efficiency losses during DC welding operations due to the inclusion of circuitry for generating AC power for TIG welding, which is not needed during DC welding.

Innovation Solution

Incorporating a DC-AC selector stage with parallel switch elements and relays, allowing for the bypassing of AC power stage components during DC welding operations, thereby reducing power losses.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If AC power stage circuitry is included for TIG welding operations, then the welding power source can perform AC TIG welding, but power losses increase during DC welding operations

Engineering Contradiction:

Improvecapability to perform AC TIG weldingVSAvoidpower losses during DC welding

Core Design Contradiction:

Adaptability or versatilityVSLoss of energy

Solution Approach 1:

The patent extracts the AC power stage circuitry from the main DC welding current path by introducing a bypass configuration. During DC welding operations, the current is routed through a separate bypass path that excludes the AC power stage components (IGBTs, diodes, capacitors), thereby removing the source of power losses while preserving the AC TIG welding capability when needed.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent segments the welding power source into distinct current paths: a DC welding path with bypass circuitry and an AC TIG welding path through the inverter stage. This segmentation allows independent optimization of each path, enabling efficient DC welding while maintaining AC TIG functionality through selective routing controlled by switching elements.

Inventive Principle:

Principle #1Segmentation

2Adaptability or versatility

If AC power stage components are present in the current path, then AC TIG welding is enabled, but conduction losses through IGBTs increase during DC welding

Engineering Contradiction:

ImproveAC TIG welding capabilityVSAvoidconduction losses through IGBTs

Core Design Contradiction:

Adaptability or versatilityVSLoss of energy

Solution Approach 1:

The patent introduces switching elements (transistors or relays) as intermediary components that control current routing. These intermediaries selectively connect or disconnect the AC power stage components from the DC welding current path, enabling the system to bypass the IGBTs during DC welding and eliminate their conduction losses while maintaining AC TIG capability when required.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Adaptability or versatility

If DC welding current passes through the DC-AC selector stage, then the stage can switch between AC and DC modes, but power losses occur through the selector stage components

Engineering Contradiction:

ImproveDC-AC selector functionalityVSAvoidpower losses through selector stage

Core Design Contradiction:

Adaptability or versatilityVSLoss of energy

Solution Approach 1:

The patent extracts the DC welding current from the DC-AC selector stage by providing a dedicated bypass path that circumvents the selector stage components during DC welding operations. This extraction eliminates the unnecessary power losses through the selector stage while preserving its DC-AC switching functionality for AC TIG welding modes.

Inventive Principle:

Principle #2Taking out (Extraction)

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 significantly reduces power losses during DC welding operations by minimizing the conduction losses through the IGBTs and rerouting the majority of the current through high-current relays, enhancing the overall efficiency of the welding power source.

Implementation Method 1

closing a relay in the bypass circuitry to bypass the IGBTs

Methodology Applied

Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 2

converting the DC power to output power suitable for the welding or cutting process via a weld process regulator

Methodology Applied

Scientific EffectElectrical inversion:

Data Source

PatentUS20250144732A1Ac power stage bypass in a welding power source

Publication Date: 2025.05.08 ESAB AB

AI summary

A welding power source (102) comprises a DC-AC selector stage (212) configurable to supply either DC weld power or AC weld power to output power terminals of the welding power source. The DC-AC selector stage comprises a first switch element (Q1) including a first switch and a first relay arranged in parallel, and a second switch element (Q2) including a second switch and a second relay arranged in parallel. A weld controller (208) controls the first and second switches and the first and second relays to select a DC power mode in which the DC weld power passes through the DC-AC selector stage to the output power terminals (130a, 103b) and to select an AC power mode in which DC weld power is converted to AC weld power and supplied to the output power terminals.