Toroidal Helix Inductive Power Transfer Coil for Wireless Charging
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Solution Overview
Problem
Existing inductive power transfer systems face inefficiencies and reliability issues due to dielectric losses and conductive proximity effects in complex wire coil structures, particularly when transferring high power over air-gaps greater than ten centimeters, which is hazardous and inconvenient for applications like electric vehicle charging.
Innovation Solution
A self-supporting elongate tubular conductor arranged in a toroidal helix with a conductive layer covering a scaffold, where each coil turn is non-coplanar and spaced uniformly, manufactured using 3D printing and additive processes to optimize spacing and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If complex wire coil structures are used to achieve high efficiency wireless power transfer, then power transfer efficiency is improved, but dielectric losses and conductive proximity effects increase
Solution Approach 1:
The patent transitions from planar coil structures to three-dimensional toroidal helical configurations. The coil windings are arranged in a toroidal geometry with vertical stacking, creating a spatial distribution that reduces proximity effects between adjacent conductors while maintaining magnetic coupling efficiency. This dimensional transformation allows the magnetic field to be concentrated in the toroidal void while separating conductors in the vertical dimension.
Solution Approach 2:
The patent employs curved toroidal geometry instead of straight or planar coil arrangements. The conductors follow circular paths in horizontal planes and are stacked vertically, creating a curved three-dimensional structure. This curvature optimizes the magnetic field distribution within the toroidal void and reduces eddy current losses by eliminating sharp corners and straight-line discontinuities in the magnetic path.
2Productivity
If high power rating is achieved for rapid vehicle charging, then charging speed is improved, but cable deterioration and safety hazards increase
Solution Approach 1:
The patent replaces mechanical cable connections with wireless inductive power transfer. The charging system uses electromagnetic coupling between transmitter and receiver coils, eliminating the need for physical plug-and-unplug operations. This substitution removes mechanical wear, contact resistance, and safety hazards associated with high-power cable connections while enabling rapid power transfer through optimized toroidal coil geometry.
3Loss of energy
If uniform spacing between coil turns is maintained, then Q factor is enhanced, but manufacturing complexity increases
Solution Approach 1:
The patent incorporates a mandrel or former around which the conductors are wound to pre-establish the toroidal helical geometry. This preliminary structure guides the conductor placement to ensure uniform spacing between turns and proper toroidal configuration. The mandrel is removed after winding, leaving a self-supporting coil structure with precisely controlled geometry that maximizes the Q factor while simplifying the manufacturing process.
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 solution achieves high efficiency in wireless power transfer by maintaining uniform spacing between coil turns, reducing dielectric losses, and enhancing the Q factor, thereby overcoming previous inefficiencies and safety concerns in high-power applications.
Implementation Method 1
inductive power transfer coil and method for making the same for use in wireless power transfer systems
Implementation Method 2
providing a conductive layer which conforms to and covers the surface of the elongate member to provide a conductive tube
Data Source
AI summary
An inductive power transfer coil and method for making the same for use in wireless power transfer systems. The inductive power transfer coil comprising an elongate member disposed around a looped path, wherein the elongate member is arranged in a helical form and the axis of the helical form is provided by the looped path so that the coil scaffold defines a toroidal void and each circuit of the looped path provides a coil turn. The elongate member is covered by a conductive layer to provide a coiled conductive tube.