Magnetic Core Particle Segmentation for DC Bias and Permeability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Magnetic cores face a trade-off between high relative magnetic permeability, withstand voltage, and DC bias characteristics due to increased packing density of magnetic powder, which leads to local magnetic saturation and degraded DC bias characteristics.
Innovation Solution
A magnetic core comprising metal magnetic powder and resin, with specific particle size distributions and spatial arrangements, where the metal magnetic powder includes small and large particles with controlled edge-to-edge distances and a resin binder to optimize packing efficiency while maintaining high permeability, withstand voltage, and DC bias characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the packing rate of magnetic powder is increased to improve relative magnetic permeability, then the relative magnetic permeability is improved, but the withstand voltage and DC bias characteristics are degraded
Solution Approach 1:
The magnetic powder is segmented into multiple particle size ranges (first range: 5-20 μm, second range: 2-5 μm, third range: 0.5-2 μm) to optimize packing structure. This segmentation allows small particles to fill voids between large particles, achieving high packing density while maintaining adequate inter-particle spacing for electrical insulation, thus resolving the contradiction between high permeability and withstand voltage characteristics.
Solution Approach 2:
The patent applies local quality by controlling the distribution of particles with different sizes in specific regions. The first particle size range forms the primary packing structure, while particles from the second and third ranges are distributed in the interstices. This local optimization ensures that critical regions maintain appropriate spacing for voltage withstanding while achieving overall high packing density for improved permeability.
2Reliability
If the packing rate of magnetic powder is increased, then the relative magnetic permeability is improved, but local magnetic saturation occurs and DC bias characteristics are degraded
Solution Approach 1:
By segmenting the magnetic powder into multiple size categories and controlling their respective content ratios (first range: 60-80 wt%, second range: 10-30 wt%, third range: 5-20 wt%), the patent creates a hierarchical packing structure. This structure prevents local magnetic saturation by ensuring that no region becomes overly dense, thereby maintaining good DC bias characteristics while achieving high overall packing rate for improved permeability.
Solution Approach 2:
The patent changes the particle size distribution parameters and their content ratios to optimize the packing structure. By adjusting the Heywood diameter ranges and weight percentage distributions of different particle size groups, the patent achieves a balance between packing density (for permeability) and inter-particle spacing (to prevent local saturation), thus resolving the contradiction in DC bias characteristics.
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
The magnetic core achieves improved withstand voltage and DC bias characteristics while maintaining high relative magnetic permeability, suitable for applications in inductors, transformers, and choke coils.
Implementation Method 1
increasing the packing rate of the magnetic powder increases the number of contact points between magnetic particles, which tends to lower a withstand voltage of the magnetic core. The increase in the number of contact points between the magnetic particles causes local magnetic saturation, and degrades DC bias characteristics.
Implementation Method 2
resin, in which a content of the metal magnetic powder satisfies 60%≤(A1/A2)≤90%
Data Source
AI summary
A magnetic core, containing metal magnetic powder and resin, in which a content of the metal magnetic powder satisfies 60%≤(A1/A2)≤90%. The metal magnetic powder includes small particles having the Heywood diameter of 1 μm or less in the cross section of the magnetic core and large particles having the Heywood diameter of 5 μm or more and less than 40 μm. An edge-to-edge distance regarding to a distance between the small particles satisfies 5≤((L1av/dav)×100)≤70. An edge-to-edge distance regarding to a distance between the small particles and the large particles satisfies 0.02 μm≤L2av≤0.13 μm and σ≤0.25 μm.