Powder Magnetic Core Insulation Mix for Permeability and Withstand Voltage
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Solution Overview
Problem
Conventional powder magnetic cores face a trade-off between permeability and withstand voltage, with reducing the amount of insulating powder increasing permeability but decreasing withstand voltage, and increasing it decreases permeability.
Innovation Solution
A powder magnetic core comprising metal magnetic substance powder, a binding agent, and insulating powder with a first insulating powder in a needle or plate shape and a second insulating powder of smaller median diameter, which are mixed and pressure-molded to achieve both high permeability and withstand voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the amount of insulating powder is increased to improve withstand voltage, then withstand voltage is improved, but permeability decreases
Solution Approach 1:
The insulating powder is segmented into two distinct size categories: first insulating powder with larger particle size (D50: 0.5-2.0 μm) and second insulating powder with smaller particle size (D50: 0.1-0.5 μm). This segmentation allows each size to fulfill different functional roles - larger particles provide insulation for withstand voltage while smaller particles fill gaps to maintain permeability
Solution Approach 2:
Different regions of the magnetic core benefit from different insulating powder sizes. The larger first insulating powder particles are strategically positioned to provide insulation between adjacent magnetic particles, while the smaller second insulating powder particles fill the interstitial spaces. This local differentiation of insulating powder quality optimizes both withstand voltage and permeability in their respective zones
2Quantity of substance
If the amount of insulating powder is reduced to increase permeability, then permeability is improved, but withstand voltage decreases
Solution Approach 1:
The patent creates a composite insulating powder system combining two different particle sizes (first insulating powder and second insulating powder) within the same binding agent matrix. This composite approach allows the system to simultaneously achieve high permeability (through small particles filling gaps) and high withstand voltage (through large particles providing insulation barriers), resolving the trade-off between these two properties
Data Source
AI summary
A powder magnetic core includes: a metal magnetic substance powder; a binding agent that binds particles of the metal magnetic substance powder; and an insulating powder provided in the binding agent. The insulating powder includes a first insulating powder and a second insulating powder each of which is in a needle shape or a plate shape. A median diameter D50 of the second insulating powder is smaller than a median diameter D50 of the first insulating powder.