Electrostatic Shielding for Wireless Power Transmission Stability
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Solution Overview
Problem
Wireless power transmission systems face issues with fluctuations in ground potential, leading to malfunctions in devices like touch panels during power transmission, especially when the power receiving device is placed on the power transmitting device and operated simultaneously.
Innovation Solution
The implementation of an electrostatic shielding section in the wireless power transmission system that shields the transmitting-side and receiving-side electrodes with respect to earth, reducing stray capacitance and stabilizing the ground potential, thereby preventing malfunctions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If electric field coupling is used for wireless power transmission, then device size can be reduced and manufacturing becomes easier, but ground potential fluctuations occur causing touch panel malfunctions
Solution Approach 1:
An electrostatic shielding electrode is introduced as an intermediary component between the power transmission electrodes and the touch panel. This shielding electrode mediates the electric field interactions, blocking direct coupling between the high-voltage power transmission field and the touch panel circuitry, thereby preventing potential fluctuations from affecting touch panel operation while maintaining the compact electric field coupling design
2Ease of operation
If the power receiving device is placed on the power transmitting device for charging, then convenient charging is achieved, but ground potential fluctuations cause malfunction of the power receiving device
Solution Approach 1:
The electrostatic shielding electrode serves as a protective intermediary that allows the power receiving device to be placed on the power transmitting device for convenient charging while blocking harmful electric field interactions. The shielding electrode maintains electrical isolation between the two devices during contact-based charging, preventing ground potential fluctuations from causing malfunctions
3Reliability
If stray capacitance between electrodes and earth is reduced to prevent potential fluctuations, then touch panel reliability improves, but device complexity increases
Solution Approach 1:
The electrostatic shielding electrode performs multiple functions simultaneously: it reduces stray capacitance between power transmission electrodes and earth, blocks electric field interference to the touch panel, and maintains reference potential stability. By consolidating these multiple protective functions into a single component, the design avoids the complexity that would arise from implementing separate solutions for each problem
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 electrostatic shielding effectively reduces ground potential fluctuations, ensuring reliable operation of touch panels and other components during power transmission, even when the capacitive input section is used.
Implementation Method 1
an electrostatic shielding section that electrostatically shields the transmitting-side electrode and the receiving-side electrode with respect to an earth
Implementation Method 2
a receiving-side electrode that is capacitively coupled to the transmitting-side electrode
Data Source
AI summary
In a power transmitting device constituting a wireless power transmission system, a voltage generating circuit applies a voltage between an active electrode and a passive electrode. In a power receiving device, a voltage generated between an active electrode that is opposed to the active electrode, and a passive electrode that is opposed to or brought into contact with the passive electrode when the power receiving device is placed on the power transmitting device is inputted to a load circuit as a power supply voltage. Passive electrodes of the power transmitting device are provided to electrostatically shield the opposed active electrodes with respect to the earth. Consequently, a wireless power transmission system, a power transmitting device, and a power receiving device are configured so the potential of the power transmitting device and the power receiving device during power transmission is stabilized to thereby prevent malfunction of the power receiving device.