Flaky Magnetic Material Structure for Low-Loss Rotating Machines
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Solution Overview
Problem
Existing soft magnetic materials fail to simultaneously achieve high saturation magnetization, high magnetic permeability, low losses, high thermal stability, and excellent mechanical characteristics, particularly at high frequencies and under large magnetic fields, which are essential for modern applications in rotating electric machines, power semiconductor devices, and high-frequency communication equipment.
Innovation Solution
A magnetic material composed of flaky magnetic metal particles with a specific thickness, aspect ratio, and intercalated phase, featuring a difference in coercivity based on direction, which enhances magnetic anisotropy and reduces hysteresis loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the saturation magnetization is increased to avoid magnetic saturation under large magnetic fields, then the magnetic permeability improves, but the hysteresis loss increases due to higher coercivity
Solution Approach 1:
The patent applies local quality by creating magnetic domains with different coercivity characteristics in different regions of the material. Specifically, it uses a composite structure where soft magnetic domains (with low coercivity for low hysteresis loss) and hard magnetic domains (with high coercivity for high saturation magnetization) coexist in spatial separation, allowing each region to perform its specialized function
Solution Approach 2:
The patent employs composite materials by combining multiple magnetic phases or domains with different magnetic properties within a single material system. This composite approach allows the material to simultaneously exhibit both low hysteresis loss characteristics and high saturation magnetization characteristics that would be contradictory in a homogeneous material
2Loss of energy
If the electrical resistance is increased to reduce eddy current loss, then the core loss decreases, but the magnetic permeability is reduced
Solution Approach 1:
The patent applies segmentation by dividing the magnetic material into fine magnetic domains or particles separated by non-conductive boundaries. This segmentation interrupts the paths for eddy currents, effectively increasing the electrical resistance to eddy currents while maintaining magnetic permeability through the distributed magnetic domains
Solution Approach 2:
The patent uses dimensional approach by creating a multi-scale structure where magnetic domains are arranged in specific spatial configurations (such as layered or hierarchical structures). This dimensional arrangement allows magnetic flux to pass effectively through the material while eddy currents are constrained by the dimensional boundaries, reducing their path length and overall loss
3Loss of energy
If the ferromagnetic resonance frequency is increased by increasing the anisotropic magnetic field, then the ferromagnetic resonance loss decreases, but the coercivity increases leading to higher hysteresis loss
Solution Approach 1:
The patent applies local quality by creating regions with different anisotropic magnetic field characteristics. Soft magnetic domains have low anisotropic fields for low coercivity and hysteresis loss, while hard magnetic domains have high anisotropic fields that push the ferromagnetic resonance frequency higher, reducing ferromagnetic resonance loss in those regions
4Volume of stationary object
If the magnetic permeability is maximized to reduce equipment size, then the saturation magnetization must be increased, but this leads to magnetic saturation under large magnetic fields
Solution Approach 1:
The patent applies dynamics by creating a magnetic material where the effective magnetic properties can adapt to the applied field strength. Under small magnetic fields, the soft magnetic domains dominate providing high permeability for compact equipment. Under large magnetic fields, the hard magnetic domains become active, increasing the overall saturation magnetization to prevent magnetic saturation
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 material achieves high magnetic permeability, low losses, and improved mechanical properties, enabling efficient operation in high-frequency environments and complex shapes, thus enhancing the performance of rotating electric machines and other devices.
Implementation Method 1
In order to make the eddy current loss small, it is effective to increase the electrical resistance, decrease the sizes of metal parts
Implementation Method 2
In order to make the hysteresis loss small, it is effective to reduce coercivity or increase the saturation magnetization
Implementation Method 3
the magnetic material includes the intercalated phase at a volume ratio of from 4% to 17% and includes voids at a volume ratio of 30% or less, and an average orientation angle between the flat surface and the plane of the magnetic material is 10° or less
Data Source
AI summary
A magnetic material of the embodiments is a magnetic material including: a plurality of flaky magnetic metal particles, each flaky magnetic metal particle having a flat surface; and an intercalated phase existing between the flaky magnetic metal particles and containing at least one second element selected from the group consisting of oxygen (O), carbon (C), nitrogen (N), and fluorine (F), in which the magnetic material includes the intercalated phase at a volume ratio of from 4% to 17% and includes voids at a volume ratio of 30% or less, and an average angle of orientation between the flat surface and a plane of the magnetic material is 10° or less.