Wireless Charging Coil PCB Structure Proximity Effect
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Solution Overview
Problem
The proximity effect between coils in wireless charging coil structures leads to increased coil impedance and reduced transmitting efficiency, especially at high frequencies, and degrades heat dissipation in multi-layer printed circuit board (PCB) designs.
Innovation Solution
A wireless charging coil PCB structure is designed with at least two layers where coils are arranged such that each layer has non-coil regions, and conductive wires with electric contacts connect partial wires of one coil to corresponding wires on another layer in parallel, minimizing the non-coil region and adjusting inductance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If multiple coils are arranged in stacked multi-layer PCB structure to cover desired charging range, then charging coverage is improved, but proximity effect between coils occurs causing increased impedance and reduced transmitting efficiency
Solution Approach 1:
The patent segments the coil structure into multiple independent layers, with each layer containing complete coil windings that are electrically isolated from other layers. This segmentation prevents the proximity effect between coils on different layers while maintaining comprehensive charging coverage through the multi-layer arrangement.
Solution Approach 2:
The patent extracts and eliminates the non-coil regions from the PCB structure, allowing coil windings to extend across the entire PCB surface area. This maximizes the active charging area while ensuring that all coil segments are properly isolated, thereby preventing unwanted electromagnetic interactions between layers.
2Ease of manufacture
If non-coil regions are maintained in PCB design for manufacturing simplicity, then ease of manufacture is improved, but charging efficiency is reduced due to smaller effective coil area
Solution Approach 1:
The patent completely removes non-coil regions from the PCB design, allowing the coil pattern to occupy the entire PCB surface. This extraction of unnecessary non-coil areas maximizes the effective charging area and improves charging efficiency while maintaining standard PCB manufacturing processes.
Solution Approach 2:
The patent merges the coil winding pattern with the entire PCB surface area, eliminating the distinction between coil regions and non-coil regions. This merging allows the full PCB area to contribute to charging functionality while using conventional PCB manufacturing techniques.
3Ease of manufacture
If coil windings are arranged to provide adequate spacing for manufacturing, then ease of manufacture is improved, but inductance balance and charging uniformity are degraded
Solution Approach 1:
The patent applies different winding densities and patterns to different local regions of the PCB to achieve uniform inductance distribution. By adjusting the local coil characteristics in different areas, the patent ensures consistent charging performance across the entire surface while maintaining manufacturability.
Solution Approach 2:
The patent modifies winding parameters such as trace width, spacing, and turn density to optimize both manufacturability and inductance balance. By carefully controlling these parameters, the patent achieves adequate manufacturing clearance while maintaining balanced inductance values across all coil segments.
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 reduces coil impedance, enhances charging efficiency, and improves heat dissipation by minimizing the non-coil region and allowing for adjustable inductance, thereby overcoming the proximity effect and increasing power transmission efficiency.
Implementation Method 1
Wireless Charger (WLC) is a cordless power transmission technology using electromagnet induction. When the power receiving module 20 is in proximity of the power transmitting module 10 and electrical current flows through the transmitting-end coil 11 to generate magnetic field, the receiving-end coil 21 of the power receiving module 20 will generate electrical current induced by the magnetic field.
Data Source
AI summary
A wireless charging coil PCB structure includes a first coil disposed on a first layer of PCB, where a center or peripheral of the first coil is a first non-coil region; a second coil disposed on a second layer of PCB, where a center or peripheral of the second coil is a second non-coil region; first conductive wires on the first non-coil region; and second conductive wires on the second non-coil region. Electric contacts are arranged between the first conductor and the second coil, and electrically connected in parallel to the first conductive wires and the portion of the second coil. Electric contacts are arranged between the second conductor and the first coil, and electrically connected in parallel to the second conductive wires and the portion of the first coil. The amount of charge is increased in the coil and resistance is reduced to overcome proximity effect.