Parallel Litz-Wire Transmitter Coil for Slim Wireless Charging
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Solution Overview
Problem
Mid-power wireless charging faces challenges due to induced voltages ranging from several tens of volts to several hundreds of volts, making it difficult to apply wireless charging modules to devices like laptop computers that require compact size and light weight, while existing solutions struggle with power transmission efficiency and overheating.
Innovation Solution
A wireless power transmitter with a primary coil formed by spirally winding subcoils in parallel, using litz wire, and a secondary coil configured with multiple subcoils to achieve efficient power transmission while minimizing size and weight, along with a shielding unit to prevent overheating and electromagnetic interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If wireless charging module size is reduced for compact devices, then device portability is improved, but power transmission efficiency deteriorates due to induced voltages of several tens to hundreds of volts
Solution Approach 1:
The wireless charging module is divided into multiple subcoils (first subcoil, second subcoil, third subcoil, fourth subcoil) arranged in a specific pattern. This segmentation allows the system to maintain compact size while achieving the required power transmission efficiency through optimized magnetic field distribution and reduced eddy current losses.
Solution Approach 2:
Different regions of the wireless charging module are designed with different characteristics. The subcoils are positioned and configured to create optimized magnetic field distribution in different areas, allowing efficient power transmission in the center region while maintaining compact overall dimensions. The shielding unit is also strategically placed to provide localized electromagnetic interference protection.
2Weight of moving object
If wireless charging module size is reduced, then device weight is reduced, but overheating increases due to concentrated power density
Solution Approach 1:
The power transmission function is divided across multiple subcoils, distributing the power density and heat generation across different regions. This prevents concentrated overheating in a single location while maintaining the compact and lightweight design of the wireless charging module.
Solution Approach 2:
A shielding unit is introduced as an intermediary component between the subcoils and the device being charged. This shielding unit serves multiple functions: it provides electromagnetic interference protection, acts as a heat sink to dissipate concentrated heat, and improves overall power transmission efficiency by optimizing the magnetic field distribution.
3Loss of energy
If subcoils are connected in parallel with spiral winding, then power transmission efficiency is improved, but manufacturing complexity increases
Solution Approach 1:
The coil structure is segmented into four separate subcoils that can be manufactured independently using standard PCB or wire-winding techniques. This segmentation simplifies the manufacturing process compared to creating a single complex coil, while the parallel connection of these standardized subcoils achieves the required power transmission efficiency.
Solution Approach 2:
Multiple standardized subcoils are combined through parallel electrical connection to achieve the desired performance. This merging approach allows each subcoil to be manufactured using simple, well-established processes, while the combined structure delivers superior power transmission efficiency compared to a single complex coil design.
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 enables efficient power transmission with a slim design, maintaining high power efficiency and preventing overheating, thus expanding the application range to include devices that require compact and lightweight form factors.
Implementation Method 1
a primary coil forming magnetic coupling with a secondary coil provided in a wireless power receiver and transmitting wireless power to the wireless power receiver
Implementation Method 2
the subcoil is litz wire consisting of several conducting wires packed in a bundle
Data Source
AI summary
A wireless power transmitter according to one embodiment of the present disclosure comprises a primary coil forming magnetic coupling with a secondary coil provided in a wireless power receiver and transmitting wireless power to the wireless power receiver, wherein the primary coil is formed by spirally winding a plurality of subcoils connected electrically in parallel while keeping the subcoils in contact with each other, and the subcoil is litz wire consisting of several conducting wires packed in a bundle.