Grain-Oriented Electrical Steel Grooves for Lower Transformer Building Factor
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Solution Overview
Problem
The challenge is to develop a grain-oriented electrical steel sheet with reduced iron loss that maintains high magnetic flux density and improves the building factor when assembled into a transformer, as existing methods either increase rotational iron loss or deteriorate magnetic properties due to groove formation.
Innovation Solution
A grain-oriented electrical steel sheet with linear grooves and recessed defects is developed, where the recessed defects are strategically placed in non-grooved portions to disrupt the extension of linear grooves, optimizing the distribution of auxiliary magnetic domains and reducing rotational iron loss without compromising magnetic properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If groove depth and width are increased to improve magnetic domain refining, then iron loss is reduced, but magnetic flux density deteriorates
Solution Approach 1:
The patent uses partial action by forming recessed defects with controlled dimensions (depth of 5-50 μm, width of 10-100 μm) that are smaller and more numerous than traditional groove structures. This partial modification approach achieves magnetic domain refining effect without excessively removing material, thereby maintaining magnetic flux density while still reducing iron loss.
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 approach effectively reduces the building factor while maintaining high magnetic flux density and iron loss performance, making it suitable for transformer applications by optimizing the distribution of recessed defects and discontinuous portions within the steel sheet.
Implementation Method 1
introducing magnetic flux non-uniformity into a steel sheet... to subdivide the width of 180° magnetic domain (main magnetic domain) formed along the rolling direction, thereby reducing iron loss
Implementation Method 2
an electrolytic etching method in which grooves are formed on the surface of a steel sheet by electrolytic etching
Data Source
AI summary
Provided is a linear groove formation pattern with which both an effect of reducing the building factor and a high magnetic flux density can be obtained. In a grain-oriented electrical steel sheet having a plurality of linear grooves extending in a direction crossing a rolling direction of the steel sheet on a surface of the steel sheet, a surface of the steel sheet between the linear grooves has a recessed defect that is recessed from the surface, a volume fraction of the recessed defect in the steel sheet is 0.0025 vol % or more and 0.01 vol % or less of a steel sheet without the recessed defect, and discontinuous portions that disrupt the extension of the linear grooves are provided at a frequency of 30 or more and 200 or less per square meter of the steel sheet.