Multipole Coil Structures for Wireless Energy Transfer Stray Field Reduction
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Solution Overview
Problem
Existing wireless energy transfer technologies face challenges in efficiently transferring power while minimizing stray fields and ensuring safe operation, particularly in scenarios where vehicles are in motion or charging is required in non-designated areas.
Innovation Solution
The use of multipole coil structures that approximate non-radiating currents, allowing for the design of a reactive near field with controlled power density and spatial structure, reducing stray fields and enabling focused power transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If traditional coils are used for wireless power transfer, then the system is simple to implement, but the stray field increases and power density cannot be controlled
Solution Approach 1:
The traditional single coil structure is segmented into multiple coils arranged in a multipole configuration. Each coil is individually controlled to create a superposition of magnetic fields that approximates a non-radiating current distribution, thereby reducing stray fields while maintaining power transfer functionality.
Solution Approach 2:
The multipole coil structure creates locally optimized magnetic field distributions with different properties in different regions. The field is concentrated and controlled in the desired transfer region while being minimized in surrounding areas, achieving spatially varying field quality that reduces stray fields.
2Use of energy by moving object
If traditional coils are used, then the device complexity is low, but the power density and spatial structure of the reactive near field cannot be designed according to specific goals
Solution Approach 1:
The system dynamically adjusts the current in each multipole coil based on real-time positioning and loading conditions. This dynamic control enables the reactive near field to be continuously optimized for specific power density requirements and spatial structures according to design goals, rather than having a fixed field pattern.
Solution Approach 2:
The system changes multiple parameters including current magnitude, phase, and frequency in each multipole coil to achieve the desired power density and spatial field structure. By independently controlling these parameters across multiple coils, the system can tailor the electromagnetic field to specific design requirements.
3Loss of energy
If multipole coil structures are used to approximate non-radiating current, then stray field is reduced and power is focused, but the device complexity increases
Solution Approach 1:
Multiple individual coil structures are merged into a unified multipole system that functions as a single integrated power transfer device. The combined effect of the multipole coils creates a focused energy transfer path with reduced stray fields, achieving improved efficiency that compensates for the increased structural complexity.
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 enhances the efficiency and safety of wireless energy transfer by minimizing stray fields and allowing for power transfer in various environments, including moving vehicles, by concentrating the energy transfer to specific areas.
Implementation Method 1
Wireless power transfer is based on resonant coil structures located close to each other
Implementation Method 2
resonant coil structures located close to each other
Implementation Method 3
In order to enhance efficiency we have to control the region where the field is large
Data Source
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AI summary
An invention is disclosed which enhances efficiency and reduces the stray field of wireless power transfer. The invention makes use of special coil geometries for transmitter and receiver. The coil geometry is an approximation of a multipole current. Such currents have a faster decaying electromagnetic field compared to traditional coils. This allows higher power densities to be transferred.