Wireless Power Receiver Magnetic Layer for Eddy Current Loss Reduction
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Solution Overview
Problem
Existing wireless power receiving systems face limitations in achieving high magnetic permeability and efficiency due to the thickness constraints of soft magnetic layers, particularly when using ferrite sheets or composite materials with polymer resin, which affect magnetic flux density and permeability.
Innovation Solution
The use of a metal ribbon as a soft magnetic layer with a uniform pattern of cracks formed on it, optimizing the permeability and reducing eddy current loss, enhances the efficiency of wireless power transfer by improving magnetic permeability and saturation magnetism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a ferrite sheet is used as a soft magnetic layer, then magnetic permeability is good, but thickness is limited due to high-temperature firing and magnetic flux density constraints
Solution Approach 1:
The patent changes the material parameter from ferrite sheet to metal ribbon, which fundamentally alters the magnetic properties. Metal ribbon enables both high magnetic permeability and high saturation magnetism while achieving thin thickness (e.g., 10 μm), resolving the contradiction between magnetic performance and thickness constraints.
2Length of stationary object
If a composite sheet containing metal powder and polymer resin is used, then thickness can be reduced, but magnetic permeability becomes lower
Solution Approach 1:
The patent uses a metal ribbon that is a non-crystalline or nanocrystalline alloy (composite material at atomic level) with specific composition ratios (Fe 70-90%, B 5-15%, Si 5-15%). This composite structure achieves both thin thickness and high magnetic permeability simultaneously, overcoming the limitations of metal powder-polymer composites.
3Force
If a metal ribbon is used as a soft magnetic layer, then high magnetic permeability and magnetic flux density are achieved with thin thickness, but eddy current loss increases at wireless charging frequencies
Solution Approach 1:
The patent applies segmentation by forming insulating cracks that divide the metal ribbon into multiple isolated regions. This segmentation interrupts eddy current paths, significantly reducing eddy current loss while preserving the high magnetic permeability of the metal ribbon material itself.
Solution Approach 2:
The patent converts the harmful continuous structure that causes eddy current loss into a beneficial segmented structure. The insulating cracks, which might seem to disrupt magnetic continuity, actually benefit the system by eliminating eddy current losses and improving overall efficiency at wireless charging frequencies.
4Force
If the thickness of the soft magnetic layer is increased to improve magnetic flux density, then magnetic performance improves, but the overall device size increases
Solution Approach 1:
The patent changes the material parameters by using nanocrystalline or non-crystalline metal alloys with optimized composition ratios. This material parameter change enables achieving high magnetic flux density with significantly reduced thickness compared to conventional ferrite sheets, resolving the contradiction between magnetic performance and device size.
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 a slim, high-efficiency wireless power transfer system with increased actual permeability and predictable performance, particularly in the frequency range used for wireless charging, by minimizing eddy current loss and ensuring uniform magnetic field distribution.
Implementation Method 1
Wireless power transmitting/receiving technology is a technology which wirelessly supplies power to electronic devices
Implementation Method 2
magnetic permeability is good, however, there is a limitation related to a thickness of the soft magnetic layer due to the limitation related to the high-temperature firing and magnetic flux density
Data Source
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AI summary
A wireless power receiving apparatus which wirelessly charges power according to one embodiment of the present invention includes a substrate, a soft magnetic layer which is laminated on the substrate and is formed with a plurality of patterns including at least 3 lines radiated from predetermined points, and a coil which is laminated on the soft magnetic layer and receives electromagnetic energy radiated from a wireless power transmitting apparatus.