Aligned Magnetic Cores via Multidirectional Field Sintering
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Solution Overview
Problem
Conventional magnetic core processing often requires a trade-off between good magnetic properties and low core loss, sacrificing one property for the other, especially in high-frequency applications.
Innovation Solution
The method involves aligning magnetic grains in a magnetic core using a specific, multidirectional magnetic field that mimics the magnetic flux path, either through inner and outer magnets or electric circuits, during the sintering or bonding process, to enhance permeability and flux density while reducing core loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If lamination thickness is reduced through mechanical rolling, then eddy-current loss is reduced, but manufacturing complexity and cost increase
Solution Approach 1:
The patent changes the fundamental parameter of core formation from mechanical rolling of thick laminations to sintering of thin magnetic powder particles. This parameter change enables achieving thin effective lamination thickness (reducing eddy-current loss) through the inherent particle size and insulating coating of the powder, rather than through complex mechanical rolling processes that require precise control of thickness and alignment.
Solution Approach 2:
The patent replaces the mechanical rolling system with a thermal sintering system. Instead of using mechanical rollers to create thin laminations, the process uses magnetic powder that is compacted and sintered into the final core shape. This substitution eliminates the need for complex mechanical rolling equipment and processes while achieving the same or better eddy-current loss reduction.
2Loss of energy
If Si and Al content is increased to reduce eddy-current loss, then core loss is reduced, but magnetic properties such as permeability and flux density deteriorate
Solution Approach 1:
The patent applies local quality by providing insulating characteristics at the particle level through coating individual magnetic powder particles with insulating material. This localized insulation between particles achieves eddy-current loss reduction without requiring bulk addition of Si and Al that would degrade the overall magnetic properties of the core material.
Solution Approach 2:
The patent creates a composite structure where magnetic powder particles are coated with insulating material. This composite approach combines the high magnetic permeability and flux density of the magnetic powder with the electrical insulation properties of the coating, achieving both low core loss and good magnetic properties simultaneously.
3Loss of energy
If magnetic powder is sintered directly into bulk core, then core loss is reduced, but flux density and permeability are reduced due to binder use
Solution Approach 1:
The patent extracts or removes the binder from the core formation process entirely. By using magnetic powder that is compacted and sintered without any binder, the invention eliminates the source of flux density and permeability reduction that plagues bonded magnetic cores, while still achieving the low core loss benefits of powder-based construction through the insulating coated particles.
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 allows for the formation of magnetic cores with improved directional permeability and flux density without significant sacrifice of magnetic properties, suitable for applications like inductors, transformers, and electric vehicle motors, while maintaining low core loss.
Implementation Method 1
aligning magnetic grains in a magnetic core using a specific, multidirectional magnetic field that mimics the magnetic flux path, either through inner and outer magnets or electric circuits
Implementation Method 2
The fixture may include one or more inner magnets configured to be located in an interior of the core, the inner magnets configured to generate a magnetic field in the magnetic core and align the grains in a plurality of directional alignments
Implementation Method 3
one or more inner wires configured to be located in an interior of the core and to carry electric current in a first direction and one or more outer wires configured to be located exterior to the core and to carry electric current in a second direction, opposite the first
Data Source
AI summary
Magnetic cores and method and fixtures for forming the same are disclosed. The magnetic core may comprise a magnetic body including magnetic grains and a magnetic flux path, the magnetic grains aligned in a plurality of distinct directional alignments to conform to the magnetic flux path. The grain orientation of the cores may be provided by fixtures including electrical circuits and/or permanent magnets. The fixtures may be configured to produce magnetic fields that approximate, mimic, or correspond to a magnetic flux path in the magnetic core, once it is consolidated and in use. The magnetic fields may orient the grains of the magnetic core when they are in an unconsolidated state, such that the grains are aligned in a plurality of directional alignments that approximate, mimic, or correspond to a magnetic flux path in the magnetic core.