Wireless Power Transmitter Metal Layer Eddy Current Suppression
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Solution Overview
Problem
Wireless power transmission systems experience efficiency loss due to eddy currents induced in metal surfaces, such as desks, when using magnetic field coupling, leading to heat loss and reduced power transmission efficiency.
Innovation Solution
A wireless power transmitting apparatus with a loop conductor and a metal layer covering one face, using materials like aluminum or copper with low relative magnetic permeability and resistivity, positioned to minimize eddy current influence, and maintaining the resonant frequency constant, while keeping the height of the loop conductor low.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a power transmitting coil is placed on a metal surface (e.g., metal desk), then wireless power transmission can be achieved, but eddy current flows through the metal portion causing heat loss and decreased power transmission efficiency
Solution Approach 1:
A nonmagnetic casing (intermediary layer) is introduced between the power transmitting coil and the metal surface. This casing prevents direct magnetic field interaction with the metal surface, thereby suppressing eddy current generation while allowing the wireless power transmission system to function normally on metal surfaces
2Loss of energy
If a nonmagnetic casing is used to cover the power transmitting coil, then eddy current is suppressed, but the system requires accurate facing of primary and secondary cores which complicates the structure
Solution Approach 1:
The invention extracts and eliminates the ferrite core component from the power transmitting apparatus, using only a simple loop conductor configuration. This removes the need for complex core alignment between primary and secondary sides, while still achieving eddy current suppression through the nonmagnetic casing
3Loss of energy
If the loop conductor is positioned higher above the supporting structure, then eddy current is suppressed, but the height of the apparatus increases
Solution Approach 1:
The nonmagnetic casing acts as an intermediary barrier that suppresses eddy current at the interface between the loop conductor and metal surface, allowing the loop conductor to maintain a low position while still preventing harmful eddy current effects
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 suppresses eddy current loss and maintains power transmission efficiency, reducing the impact of the supporting structure's material on the system, without increasing the height of the loop conductor.
Implementation Method 1
a loop conductor (11) for power transmission having an inductance; an inverter circuit (13) that receives a DC voltage, converts the DC voltage into an AC voltage, and applies the AC voltage to the loop conductor
Implementation Method 2
a metal layer (14) that covers one of faces formed by the loop conductor (11) farthest from a power receiving apparatus (200)... eddy current loss is suppressed
Data Source
AI summary
A wireless power transmitting apparatus includes: a loop conductor for power transmission having an inductance; an inverter circuit configured to receive a DC voltage, convert the DC voltage into an AC voltage, and apply the AC voltage to the loop conductor; a capacitor connected between one end of the loop conductor and at least one end of the inverter circuit; and a metal layer covering one of the faces formed by the loop conductor farthest from a power receiving apparatus.