Overlapping Planar Coil Layout for Low-Loss Wireless Power Transfer
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Solution Overview
Problem
Existing wireless power transfer systems using planar coils experience high electrical resistance, leading to inefficient power transfer, particularly in applications like electric vehicles where space constraints are severe.
Innovation Solution
A coil component comprising a first and second planar coil that overlap with a gap and are not connected, along with a capacitor forming a resonant circuit, and a magnetic member that holds and covers the coils, optimizing their alignment and reducing eddy current loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If planar coils are used for wireless power transfer, then manufacturing efficiency is improved and space constraints are satisfied, but electrical resistance increases leading to poor power transfer
Solution Approach 1:
The planar coil is divided into multiple segments (first planar coil and second planar coil) that are arranged in series. Each segment has optimized dimensions (thickness of 0.15mm or more and 0.35mm or less) to balance manufacturing ease with electrical performance, allowing the overall coil to achieve low resistance while maintaining manufacturability
Solution Approach 2:
The invention optimizes specific parameters of the planar coil including thickness (0.15-0.35mm), width, and length to minimize electrical resistance. By carefully controlling these parameters, the coil achieves both ease of manufacture and efficient power transfer, resolving the contradiction between manufacturing convenience and electrical performance
2Power
If high-frequency current is used for wireless power transfer, then power transfer capability is improved, but skin effect increases AC resistance and power consumption
Solution Approach 1:
The invention changes the physical parameters of the conductor including increasing thickness to 0.15mm or more and 0.35mm or less, which reduces the impact of skin effect at high frequencies. This parameter optimization allows high-frequency operation for adequate power transfer while minimizing AC resistance and energy loss
3Reliability
If litz wire is used to suppress skin effect, then power transfer efficiency is improved, but manufacturing cost and time increase significantly
Solution Approach 1:
The invention replaces expensive litz wire with a simpler planar coil structure made from standard conductive materials. While litz wire provides good skin effect suppression, the planar coil achieves comparable performance at much lower manufacturing cost and complexity by using conventional fabrication processes
Solution Approach 2:
The invention substitutes the mechanical twisting structure of litz wire with a planar printed circuit board approach. This replacement maintains electrical performance while dramatically simplifying manufacturing, eliminating the need for complex wire twisting and assembly processes
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 configuration enhances power transfer efficiency by minimizing electrical resistance and eddy current loss, enabling effective power transfer in constrained spaces.
Implementation Method 1
a power transfer system of a magnetic field resonance method
Implementation Method 2
a high-frequency current is caused to flow through a resonant circuit including a coil
Implementation Method 3
a skin effect may occur in the coil. The skin effect increases the AC resistance, which increases the power consumption due to generation of heat
Implementation Method 4
a magnetic member that holds and covers the coils, optimizing their alignment and reducing eddy current loss
Data Source
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AI summary
A coil component 10 according to one embodiment includes a first planar coil 11, a second planar coil 12 that overlaps the first planar coil 11 and is not connected to the first planar coil 11, and a capacitor 70 that is connected to one of the first planar coil 11 and the second planar coil 12 and constitutes a resonant circuit together with the first planar coil or the second planar coil 12 to which the capacitor 70 is connected. The second planar coil 12 has a thickness of 0.15 mm or more and 0.35 mm or less.