Ferrite Notch Design for Wireless Power Receiving Coil
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Solution Overview
Problem
Contactless electric power transmission systems face a reduction in coupling coefficient due to the inefficient use of ferrite material, leading to increased manufacturing costs and reduced magnetic flux interlinkage between power transmission and receiving coils.
Innovation Solution
The electric power receiving/transmission device incorporates notch portions in the ferrite to reduce the amount of ferrite needed while maintaining a high coupling coefficient, with the notch portions overlapping the side portions of the power receiving/transmission coil, thereby increasing the magnetic flux interlinkage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a conventional ferrite configuration without notch portions is used, then the ferrite provides sufficient magnetic flux path, but the amount of ferrite material is excessive leading to increased manufacturing costs
Solution Approach 1:
The invention extracts unnecessary ferrite material by introducing notch portions into the ferrite structure. These notches remove ferrite from regions where it does not contribute effectively to magnetic flux interlinkage, thereby reducing material quantity and manufacturing cost while preserving the essential magnetic flux path functionality.
Solution Approach 2:
The ferrite structure is modified locally by adding notch portions at specific locations. This creates non-uniform local quality in the ferrite, concentrating the magnetic flux path in regions of higher need (near the coil) while removing material from regions where flux density is already low, thus optimizing material distribution.
2Ease of manufacture
If the ferrite is reduced in amount to lower manufacturing costs, then manufacturing cost decreases, but the coupling coefficient between power transmission and receiving coils is reduced
Solution Approach 1:
The notch portions create local quality variations in the ferrite that concentrate magnetic flux paths in critical regions. By strategically placing notches, the ferrite structure maintains high magnetic permeability where needed (near the coil windings) while reducing material elsewhere, thus preserving coupling coefficient despite overall material reduction.
Solution Approach 2:
The ferrite structure transitions from a symmetric conventional design to an asymmetric design with notch portions. This asymmetric configuration optimizes the magnetic flux distribution by creating preferential flux paths that enhance coupling between coils, compensating for the reduced total ferrite volume.
3Reliability
If the ferrite configuration is optimized to increase magnetic flux interlinkage, then the coupling coefficient improves, but the device complexity increases
Solution Approach 1:
The ferrite is segmented by introducing notch portions that divide the continuous ferrite structure into distinct regions. This segmentation creates separate magnetic flux paths that are optimized for different functional zones, improving flux interlinkage efficiency while the modular nature of the segmentation keeps manufacturing complexity manageable.
4Reliability
If conventional ferrite shape is used, then manufacturing is simple, but magnetic flux path efficiency is suboptimal leading to reduced coupling coefficient
Solution Approach 1:
The ferrite manufacturing process is enhanced with local quality modifications through the addition of notch portions. These notches are integrated into the molding or machining process, allowing the complex shape to be produced with minimal additional manufacturing steps, thus balancing manufacturing simplicity with flux path efficiency.
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 configuration reduces manufacturing costs and enhances the coupling coefficient by optimizing the magnetic flux path, ensuring efficient power transfer between the power transmission and receiving coils.
Implementation Method 1
When AC current flows through the power transmission coil, magnetic flux is formed around the power transmission coil
Implementation Method 2
The magnetic flux incident upon the ferrite flows in the ferrite, and reaches the hollow portion of the power transmission coil
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
An electric power receiving device includes a ferrite (72), and a power receiving coil (8) in which a hollow portion is formed. The power receiving coil (8) is formed so as to surround a winding axis that extends in the thickness direction. When the power receiving coil (8) and the ferrite (72) are viewed from an observation position spaced apart from the power receiving coil (8) in a direction in which the winding axis extends, notch portions (92) are formed in an outer peripheral portion of the ferrite (72) such that the notch portions overlap side portions of the coil. The width of each notch portion (92) as measured in a circumferential direction of the power receiving coil (8) increases in a direction away from the hollow portion of the power receiving coil (8).