Grain-oriented steel sheet for transformer iron loss reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing techniques for magnetic domain refining in grain oriented electrical steel sheets, such as forming linear grooves, have limited effectiveness in reducing iron loss in actual transformers, and often result in a poor building factor.
Innovation Solution
The use of a forsterite film with a thickness of 0.3 µm or more at the bottom portions of linear grooves, combined with a tension coating to increase film tension to 10.0 MPa or higher, effectively reduces eddy current loss and maintains a high building factor by optimizing the magnetic domain refining treatment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If linear grooves are formed on the steel sheet surface for magnetic domain refinement, then magnetic domain width is reduced, but iron loss reduction effect is insufficient and building factor deteriorates
Solution Approach 1:
The invention applies local quality by forming linear grooves only at specific locations (edges and/or centers of the steel sheet) rather than uniformly across the entire surface. This localized approach refines magnetic domains where they are most impactful while preserving the overall building factor of the steel sheet.
Solution Approach 2:
The invention uses a composite structure combining the steel sheet base material with linear groove features. The grooves create a composite morphology that introduces high dislocation density regions and refines magnetic domains, achieving superior iron loss reduction while maintaining structural integrity and building factor.
2Loss of energy
If laser irradiation is used to introduce high dislocation density regions, then magnetic domain width is reduced, but manufacturing complexity and cost increase
Solution Approach 1:
The invention replaces complex laser irradiation processes with a simpler mechanical or chemical groove formation process. By forming linear grooves through conventional means rather than requiring sophisticated laser equipment and precise control systems, the manufacturing complexity is significantly reduced while achieving comparable or superior magnetic domain refinement effects.
3Manufacturing precision
If deep linear grooves are formed to refine magnetic domains, then magnetic domain width is reduced, but the effect on actual transformer iron loss is minimal
Solution Approach 1:
The invention optimizes the parameters of the linear grooves, including depth, width, spacing, and location, to achieve the optimal balance between magnetic domain refinement and iron loss reduction. By carefully controlling these geometric parameters and combining groove formation with appropriate heat treatment, the invention maximizes the effectiveness of magnetic domain refinement in reducing actual transformer 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 significantly reduces iron loss in transformers while maintaining a high building factor, as evidenced by a proportion of eddy current loss of 65% or less, thereby enhancing the magnetic properties of the steel sheet.
Implementation Method 1
the use of a forsterite film with a thickness of 0.3 µm or more at the bottom portions of linear grooves, combined with a tension coating to increase film tension to 10.0 MPa or higher, effectively reduces eddy current loss
Implementation Method 2
forming linear grooves having a depth of more than 5μm on the base iron portion of a steel sheet after final annealing at a load of 882 to 2156 MPa (90 to 220 kgf/mm 2)
Data Source
Figure 1~2
AI summary
Disclosed is a grain oriented electrical steel sheet that may reduce iron loss of material with linear grooves formed thereon for magnetic domain refinement and offer excellent low iron loss properties when assembled as an actual transformer, where the steel sheet has sheet thickness of 0.30 mm or less, linear grooves are formed at intervals of 2-10 mm in rolling direction, depth of each of the linear grooves is 10 µm or more, thickness of the forsterite film at bottom portions of the linear grooves is 0.3 µm or more, total tension applied to the steel sheet by the forsterite film and tension coating is 10.0 MPa or higher in rolling direction, and proportion of eddy current loss in iron loss W17/50 of the steel sheet is 65% or less when alternating magnetic field of 1.7 T and 50 Hz is applied to the steel sheet in the rolling direction.