Variable Magnetic Flux Magnet for Motor Efficiency
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Solution Overview
Problem
Conventional variable-magnetic-flux motors face efficiency and output limitations due to differences in magnetic force between stationary and variable-magnetic-force magnets, and the Nd—Fe—B-based rare-earth magnet's nucleation type magnetization mechanism, which requires a large external magnetic field and increases magnetic magnetization current, making it difficult to control and impractical for use as a variable-magnetic-force magnet.
Innovation Solution
A magnetic body with a residual magnetic flux density of at least 11 kG and a coercive force of 5 kOe or less, composed of a rare-earth element, transition metal, and boron, allowing reversible magnetic force change with a small external magnetic field, eliminating the need for expensive Co and achieving a pinning type magnetization mechanism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If Nd—Fe—B-based rare-earth magnet is used as variable-magnetic-force magnet, then residual magnetic flux density is improved, but external magnetic field requirement increases and control difficulty worsens
Solution Approach 1:
The patent changes the magnetization mechanism parameter by controlling crystal particle size to achieve single-domain structure, transforming the magnetization type from nucleation to pinning type. This allows the material to maintain high residual magnetic flux density while requiring smaller external magnetic fields for control.
Solution Approach 2:
The patent segments the magnetic material into fine crystal particles with specific size ranges (0.5-2.0 μm, preferably 0.8-1.5 μm) to create single-domain structures. This segmentation enables the material to exhibit pinning-type magnetization characteristics, resolving the contradiction between high residual flux density and ease of control.
2Ease of operation
If Sm2Co17 is used as variable-magnetic-force magnet, then control ease is improved, but residual magnetic flux density is insufficient
Solution Approach 1:
The patent uses composite material structure with Nd-Fe-B main phase and controlled crystal particle size to achieve both high residual magnetic flux density (≥11 kG) and pinning-type magnetization mechanism. This composite approach combines the advantages of high flux density with ease of control.
Solution Approach 2:
The patent changes the critical parameter of crystal particle size to transform the magnetization mechanism from nucleation type (Nd-Fe-B conventional) to pinning type (single-domain). This parameter change enables simultaneous achievement of high residual flux density and ease of control comparable to Sm2Co17.
3Adaptability or versatility
If larger external magnetic field is applied to change magnetization, then magnetic force reversal is achieved, but magnetic magnetization current increases and efficiency decreases
Solution Approach 1:
The patent changes the magnetization mechanism parameter by controlling crystal particle size to achieve pinning-type magnetization. This enables magnetic force reversal with smaller external magnetic fields, reducing magnetic magnetization current and energy loss while maintaining reversibility.
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 body enables high residual magnetic flux density and efficient magnetic force control with reduced external magnetic field requirements, enhancing motor output and efficiency in variable-magnetic-flux motors.
Implementation Method 1
the magnetic body in accordance with the present invention has a residual magnetic flux density Br of at least 11 kG and a coercive force HcJ of 5 kOe or less, while an external magnetic field required for the residual magnetic flux density Br to become 0 is 1.10 HcJ or less
Implementation Method 2
it is necessary for the Nd—Fe—B-based rare-earth magnet to achieve a magnetization mechanism of a pinning type as in Sm2Co17 or a single-domain particle type as in ferrite magnets
Data Source
AI summary
A magnetic body which can reversibly change its magnetic force with a small external magnetic field while having a high residual magnetic flux density is provided. The magnetic body of the present invention has a residual magnetic flux density Br of at least 11 kG and a coercive force HcJ of 5 kOe or less, while an external magnetic field required for the residual magnetic flux density Br to become 0 is 1.10 HcJ or less.