Metamaterial Backing for Wireless Power Coil Efficiency
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Solution Overview
Problem
Inductive coupling for wireless power transfer is inefficient due to misalignment and increased distance between coils, and existing solutions like ferrite backings are expensive, heavy, and brittle, limiting its practicality.
Innovation Solution
A revised coil loop structure using stacked printed circuit boards (PCBs) with metamaterials that redirect and contain the electromagnetic field, allowing for active tuning and improved efficiency, and a metamaterial backing that reduces magnetic flux leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If ferrite backings are used to improve power transfer efficiency, then electromagnetic field leakage is reduced, but the system becomes expensive, heavy, and brittle
Solution Approach 1:
The patent changes the material parameters from traditional ferrite to metamaterials with specific electromagnetic properties. The metamaterials are designed with unit cells having specific geometric parameters that control electromagnetic field interaction, achieving field containment without the weight and brittleness of ferrite materials.
Solution Approach 2:
The patent employs composite metamaterial structures composed of multiple layers and patterns (e.g., split-ring resonators, complementary split-ring resonators) that work together to control electromagnetic fields. These composite structures achieve superior performance compared to single-material ferrite backings while reducing weight and improving durability.
2Loss of energy
If ferrite backings are used to improve power transfer efficiency, then electromagnetic field leakage is reduced, but the system becomes expensive and brittle
Solution Approach 1:
The patent replaces traditional mechanical ferrite backing structures with planar metamaterial patterns that can be manufactured using standard PCB fabrication techniques. This substitution of manufacturing methodology dramatically reduces cost and complexity while eliminating the brittleness issue associated with ceramic ferrite materials.
Solution Approach 2:
The patent transforms the backing material from bulky ferrite components to thin, patterned metamaterial layers with controllable electromagnetic parameters. This parameter change enables manufacturing through conventional printed circuit board processes, making the system cost-effective and scalable.
3Loss of energy
If the coils are placed in close proximity to improve power transfer efficiency, then the effective operable area is limited
Solution Approach 1:
The patent introduces metamaterial backings as intermediary structures between the coils and the environment. These metamaterials act as field-containing boundaries that prevent energy leakage, allowing coils to be placed farther apart while maintaining efficiency, thereby expanding the effective operable area.
Solution Approach 2:
The patent adds the dimension of field control through metamaterial backings, transforming the problem from one of spatial proximity to one of electromagnetic field management. This enables power transfer over larger areas without sacrificing efficiency, as the metamaterials confine the field in the vertical dimension while allowing horizontal expansion.
4Adaptability or versatility
If the coils are misaligned to accommodate varying positions, then power transfer efficiency deteriorates
Solution Approach 1:
The patent uses metamaterial backings as intermediary field-containing structures that stabilize the electromagnetic field distribution. These metamaterials maintain field confinement and coupling even when coils are misaligned, allowing position flexibility without efficiency deterioration.
Solution Approach 2:
The metamaterial backings provide beforehand cushioning by pre-establishing field-containing boundaries that compensate for potential misalignment. This protective field structure ensures that efficiency is maintained even when positional variations occur during operation.
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 system enhances power transfer efficiency by reducing the negative effects of misalignment and distance, while being more durable, cost-effective, and adaptable to varying conditions.
Implementation Method 1
The source provides a current which flows through the generating coil to produce an electromagnetic field. The electromagnetic field propagates from the generating coil to the receiving coil and induces a voltage across the receiving coil
Implementation Method 2
The metamaterial is used as a backing for the coils and reduces the amount of magnetic flux found outside of the power transfer system. Without the metamaterial backing, magnetic flux would leak out the system and be wasted.
Data Source
AI summary
A revised coil loop structure is combined with metamaterials designed to contain and redirect the electromagnetic field to produce an improved inductive coupling system. The efficiency of the inductive power transfer system is increased relative to existing technologies by overcoming the negative effects of distance and misalignment. The transmitting and receiving coils are both constructed by connecting a series of printed circuit boards (PCBs). The individual PCBs are then stacked on top of one another and connected to produce the transmitting and receiving coils. The transmitting and receiving coils further feature a coil shape designed to allow the coils to be actively and variably tuned to one another. The efficiency of power transfer in the system is additionally increased through the use of metamaterials. The metamaterial is used as a backing for the coils and reduces the amount of magnetic flux found on the back of the coils.