Welding Transformer Iron Core Saturation Detection via Primary Current Analysis

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Solution Overview

Problem

Magnetic saturation in the iron core of welding transformers leads to undesirable current spikes, increasing power losses and reducing operational reliability, with existing solutions often requiring additional sensors that increase complexity and cost.

Innovation Solution

A method for detecting iron core saturation in welding transformers using only the measurement of the primary current, without additional sensors, through an analysis of the instantaneous value or time derivative of the primary current, employing a comparator and binary logic to identify and confirm saturation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If additional sensors are incorporated to detect iron core saturation, then saturation detection capability is improved, but device complexity and production costs increase

Engineering Contradiction:
Improvesaturation detection capabilityVSAvoidsystem complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The system uses its existing primary current measurement infrastructure to detect saturation, making the system self-diagnostic without requiring external sensors. The control unit analyzes current already being measured for welding control purposes, turning a routine measurement into a dual-purpose diagnostic tool.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The primary current measurement system serves multiple functions: both welding control and saturation detection. By analyzing the same current signal for different purposes, the system achieves multi-functionality without adding hardware, resolving the contradiction between detection capability and system complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Reliability

If additional sensors are incorporated to detect iron core saturation, then saturation detection capability is improved, but production costs increase

Engineering Contradiction:
Improvesaturation detection capabilityVSAvoidproduction cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The system uses its existing primary current measurement infrastructure to detect saturation, making the system self-diagnostic without requiring external sensors. The control unit analyzes current already being measured for welding control purposes, turning a routine measurement into a dual-purpose diagnostic tool.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The primary current measurement system serves multiple functions: both welding control and saturation detection. By analyzing the same current signal for different purposes, the system achieves multi-functionality without adding hardware, resolving the contradiction between detection capability and system complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Reliability

If additional sensors are incorporated to detect iron core saturation, then saturation detection capability is improved, but system robustness decreases

Engineering Contradiction:
Improvesaturation detection capabilityVSAvoidsystem robustness
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The system uses its existing primary current measurement infrastructure to detect saturation, making the system self-diagnostic without requiring external sensors. The control unit analyzes current already being measured for welding control purposes, turning a routine measurement into a dual-purpose diagnostic tool.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The primary current measurement system serves multiple functions: both welding control and saturation detection. By analyzing the same current signal for different purposes, the system achieves multi-functionality without adding hardware, resolving the contradiction between detection capability and system complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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

Effectively detects and prevents magnetic saturation, eliminating current spikes and enhancing the reliability and longevity of welding systems without the need for additional sensors, thus maintaining system robustness and reducing production costs.

Implementation Method 1

magnetic saturation detection within the iron core of a transformer for resistance spot welding

Methodology Applied
Scientific EffectMagnetic saturation: Magnetic Saturation

Data Source

PatentEP3079162B1Device and method for detecting the iron core saturation of a resistance spot welding transformer utilising measurement of the primary current of the transformer
Publication Date: 2019.09.04 UNIVERZA V MARIBORU
  • EP3079162B1 patent drawingFigure 1~2
  • EP3079162B1 patent drawingFigure 3
  • EP3079162B1 patent drawingFigure 4

AI summary

A device and a procedure is presented for saturation detection of a welding transformer's iron core that solves the technical problem of the saturation detection of the welding transformers' iron cores by utilising measurement of the primary current of the transformer. The existing solutions are based on the incorporation of additional sensors hence the device's structure is modified. Amongst other consequences, these modifications may alter the properties of the device, increase its complexity, increase the production costs and reduce the robustness of the entire welding system. The presented technical problem is solved in an effective and inexpensive way that is based on an analysis of the measured primary current of the welding transformer. Using utilisation of the proposed solutions, additional sensors arc unnecessary as measurement of the primary current is needed in any case due to other reasons, such as control of the welding current, protecaion, diagnostics, etc. In this way, the additional components within the welding systems arc unnecessary. Therefore, all negative effects and aspects of usage of these components involving additional sensors and auxiliary devices for the saturation detection of thc magnetic cores of the welding transformers are avoided.