Concave Ferrite Shielding for Extended-Gap Wireless Power Transfer
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing wireless power transfer systems are limited to small separation gaps between transmitter and receiver coils, typically up to 3-5 mm, which restricts their applicability in thicker objects and devices with obstructions, limiting their commercial use.
Innovation Solution
A wireless power transmitter design featuring a ferrite core shielding with a concave cavity and a coil made of Litz wire, operating at frequencies between 87 kHz and 360 kHz, allowing power transfer over extended separation gaps of up to 15 mm or more, while maintaining performance characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If legacy near-field wireless power transfer systems are used, then power transfer efficiency is maintained, but separation gap is limited to 3-5 mm
Solution Approach 1:
The patent applies a concave curvature to the ferrite core shielding structure. This curved geometry is designed to focus and direct magnetic flux toward the receiver coil, thereby extending the effective separation gap while maintaining efficient power transfer. The concave shape creates a magnetic field concentration effect that overcomes the natural field decay over distance.
Solution Approach 2:
The patent changes the operating frequency parameter from the standard Qi range to 87-360 kHz, which is optimized for extended gap operation. Additionally, the ferrite core material properties and shielding geometry are specifically designed for this frequency range to maximize magnetic coupling efficiency at larger separations.
2Adaptability or versatility
If separation gap is increased to accommodate thicker objects, then commercial applicability improves, but power transfer performance deteriorates
Solution Approach 1:
The ferrite core shielding acts as an intermediary that bridges the gap between transmitter and receiver coils. This magnetic shielding material guides and concentrates magnetic flux through the thicker objects (cabinets, countertops, device cases), enabling power transfer through obstructions that would otherwise block the magnetic field.
Solution Approach 2:
The system uses a composite structure combining ferrite core material with Litz wire coil windings. The ferrite provides high magnetic permeability to guide flux, while the Litz wire minimizes resistive losses. This composite approach enables both extended gap operation and maintained power transfer rate.
3Length of stationary object
If ferrite core shielding with concave cavity is implemented, then separation gap is extended to 15 mm or more, but device complexity increases
Solution Approach 1:
The ferrite core shielding is segmented into discrete components that can be manufactured separately and assembled. This modular approach simplifies manufacturing while achieving the complex concave geometry needed for extended gap operation. The segmentation also allows for optimization of each component's magnetic properties.
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
Enables wireless power transfer over larger separation gaps, expanding the range of commercial applications by increasing the effective charging volume and compatibility with thicker objects and devices with obstructions.
Implementation Method 1
a shielding comprising a ferrite core including a magnetic backing and a magnetic ring, the magnetic backing and magnetic ring, in combination, defining a concave cavity
Implementation Method 2
inductive wireless power transfer, which occurs when magnetic fields created by a transmitting element induce an electric field, and hence, an electric current, in a receiving element
Data Source
AI summary
A power transmitter includes a control and communications unit and an inverter circuit configured to receive input power and convert the input power to a power signal. The power transmitter further includes a shielding comprising a ferrite core including a magnetic backing and a magnetic ring, the magnetic backing and magnetic ring, in combination, defining a concave cavity, the magnetic ring defining a bottom portion, a top portion, and an inner side wall between the bottom portion and the top portion, the inner sidewall defining an outward extending shape, the outward extending shape extending radially outward from the bottom portion to the top portion. The power transmitter further includes a coil configured to transmit the power signal to a power receiver, the coil formed of wound Litz wire and positioned within the concave cavity of the shielding and radially inward from the inner wall.