Magnetic Core Particle Structure for High Permeability and Insulation
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Solution Overview
Problem
Existing magnetic cores with high relative magnetic permeability face challenges in improving withstand voltage properties due to the concentration of electric fields at particle contacts, which deteriorates their performance.
Innovation Solution
A magnetic core comprising large and small soft magnetic particles with specific aspect ratios, where the average aspect ratio of the small particles is greater than that of the large particles, and an insulating coating to enhance surface contact and reduce electric field concentration, maintaining high relative magnetic permeability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high relative magnetic permeability is achieved using amorphous alloy powder, then magnetic performance is improved, but withstand voltage property deteriorates due to electric field concentration at particle contacts
Solution Approach 1:
The patent applies local quality by creating two distinct particle size groups (large particles: 5-25 μm, small particles: 0.5-3 μm) with different aspect ratios (A1: 1.00-1.50, A2: 1.30-2.50). This local differentiation in particle characteristics allows optimization of both magnetic permeability and withstand voltage properties in different regions of the magnetic core, resolving the contradiction between magnetic performance and electrical insulation.
Solution Approach 2:
The patent uses composite materials by combining large and small amorphous alloy particles with specific aspect ratios in a controlled mixture. This composite structure leverages the advantages of both particle sizes: large particles provide magnetic permeability while small particles fill gaps and reduce electric field concentration, achieving both high magnetic performance and improved withstand voltage property.
2Loss of energy
If amorphous alloy powder is used to reduce core loss, then energy efficiency is improved, but density of the dust core during molding becomes difficult to improve
Solution Approach 1:
The patent segments the amorphous alloy powder into two distinct size groups (large particles and small particles) with specific aspect ratios. This segmentation allows the small particles to fill the interstices between large particles during molding, thereby increasing the overall density of the dust core while maintaining the low core loss characteristics of amorphous alloy material.
3Reliability
If particle aspect ratios are optimized to improve withstand voltage, then electrical performance is improved, but manufacturing complexity increases
Solution Approach 1:
The patent applies parameter changes by specifying precise aspect ratio ranges (A1: 1.00-1.50 for large particles, A2: 1.30-2.50 for small particles) and size ranges (large: 5-25 μm, small: 0.5-3 μm). These controlled parameter variations enable optimization of withstand voltage properties while providing clear manufacturing specifications that balance performance requirements with production feasibility.
Data Source
AI summary
To obtain a magnetic core having an improved relative magnetic permeability and an improved withstand voltage property and the like. The magnetic core contains large particles observed as soft magnetic particles having a Heywood diameter of 5 μm or more and 25 μm or less and small particles observed as soft magnetic particles having a Heywood diameter of 0.5 μm or more and 3 μm or less in a cross section. 1.00≤A1≤1.50, 1.30≤A2≤2.50, and A1≤A2 are satisfied, in which an average aspect ratio of the large particles is A1 and an average aspect ratio of the small particles is A2.