Angled Ferrite Structure for Wireless EV Charging Emissions
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Solution Overview
Problem
Current wireless power transfer systems for electric vehicles face challenges in reducing electromagnetic field emissions when coils are flush mounted or buried, leading to increased distances and stronger magnetic fields, which can exceed legal limits.
Innovation Solution
A multi-coil base pad with an angled ferrite structure is used to reduce emissions, featuring a double-D coil configuration where the first and second coils are positioned adjacent to each other with angled outer sides and a flat inner side, allowing for efficient power transfer while minimizing excess emissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If coils are flush mounted or buried to enable wireless power transfer, then power transfer efficiency is improved, but electromagnetic field emissions increase and may exceed legal limits
Solution Approach 1:
The patent applies local quality by creating asymmetric ferrite structures with different geometries at specific locations around the coils. The ferrite structures have varying shapes, sizes, and orientations at different positions to locally control and direct magnetic flux patterns, thereby reducing electromagnetic emissions in specific directions while maintaining power transfer efficiency.
Solution Approach 2:
The patent employs asymmetry by designing ferrite structures with non-uniform geometries, including angled surfaces, varying thicknesses, and asymmetric arrangements relative to the coils. This asymmetric configuration optimizes magnetic flux distribution to minimize emissions while preserving the beneficial power transfer characteristics.
2Object-generated harmful factors
If distance between base pad and vehicle pad is increased, then emission compliance is improved, but power transfer efficiency deteriorates
Solution Approach 1:
The patent applies parameter changes by modifying the physical and geometric parameters of the ferrite structures, including their shapes, sizes, orientations, and material properties. These parameter optimizations enable the system to maintain effective power transfer at increased distances while complying with emission regulations through controlled magnetic flux patterns.
3Object-generated harmful factors
If angled ferrite structure is implemented to reduce emissions, then electromagnetic emissions are reduced, but device complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the ferrite structure into multiple discrete components or segments positioned around the coils. Each segment can be independently optimized for emission reduction while maintaining manufacturability and assembly simplicity, thereby reducing overall device complexity compared to a monolithic complex structure.
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 angled ferrite structure design effectively reduces electromagnetic emissions by directing magnetic flux vertically and minimizing leakage, maintaining efficient power transfer to the vehicle pad while adhering to emission regulations.
Implementation Method 1
The angled ferrite structure design effectively reduces electromagnetic emissions by directing magnetic flux vertically and minimizing leakage
Implementation Method 2
An alternating current in the primary inductor produces a fluctuating magnetic field. When the secondary inductor is placed in proximity to the primary inductor, the fluctuating magnetic field induces an electromotive force (EMF) in the secondary inductor, thereby transferring power to the secondary power receiver device.
Data Source
AI summary
An apparatus for wirelessly transferring charging power is provided. The apparatus comprises a first coil, as second coil, a ferrite structure positioned on one side of the first coil and the second coil. The ferrite structure includes a first angled surface at an outer side of the first coil and a second angled surface at an outer side of the second coil. The ferrite structure further includes a substantially flat surface at an inner side of the first coil and an inner side of the second coil. The first angled surface and the second angled surface are at an angle to the flat surface.