Rotational Symmetrical Electrode Wireless Power Transmission

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Solution Overview

Problem

Existing wireless power transmission systems face inefficiencies and reduced transmission capabilities when rotated due to power loss in coils and positional displacement, leading to decreased power transmission efficiency.

Innovation Solution

A wireless power transmission system with rotationally symmetrical electrodes and inductors, where the electrodes are disposed to oppose each other across a distance of λ/2π or less as a near field, and the resonance frequencies of the couplers are set to be equal, ensuring efficient power transmission even when rotated.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If a coil is used for wireless power transmission, then power can be transmitted wirelessly, but power loss in the coil is large and transmission efficiency is low

Engineering Contradiction:
Improvepower lossVSAvoidpower transmission efficiency
Core Design Contradiction:
Loss of energyVSProductivity

Solution Approach 1:

The patent changes the fundamental operating principle from electromagnetic induction (coil-based) to electrostatic coupling (electrode-based). By using electrodes with capacitance instead of coils with inductance, and operating at resonance frequency of the capacitive coupling, the system achieves significantly reduced power loss and improved transmission efficiency.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent replaces the magnetic field-based electromagnetic induction system with an electric field-based electrostatic coupling system. This substitution eliminates the resistive losses inherent in coil-based systems and enables more efficient wireless power transmission through capacitive coupling between transmitter and receiver electrodes.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Adaptability or versatility

If the power transmission device is rotated, then flexibility and adaptability are improved, but the coil is displaced and characteristics change, reducing transmission efficiency

Engineering Contradiction:
Improverotation capabilityVSAvoidpower transmission efficiency
Core Design Contradiction:
Adaptability or versatilityVSProductivity

Solution Approach 1:

The patent employs rotationally symmetrical electrode configurations (such as circular or annular electrodes) that maintain their electrical characteristics regardless of rotational position. This symmetry ensures that the capacitance and resonance frequency remain constant during rotation, preserving transmission efficiency while enabling flexible positioning and orientation adjustments.

Inventive Principle:
Principle #4Asymmetry

3Productivity

If electrodes are disposed close together to reduce distance, then coupling efficiency is improved, but electric field interference and breakdown risk increase

Engineering Contradiction:
Improvecoupling efficiencyVSAvoidelectric field interference
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent divides the power transmission system into separate transmitter and receiver devices with distinct electrode configurations. The transmitter electrodes are separated from receiver electrodes by a controlled distance, creating discrete capacitive coupling zones. This segmentation allows efficient power transfer while maintaining safe electric field levels and preventing breakdown through proper spacing and voltage distribution.

Inventive Principle:
Principle #1Segmentation

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 system achieves high transmission efficiency, maintaining power transfer efficiency of 90% or more even when rotated, by aligning the electrodes and inductors to maintain optimal resonance and minimize interference.

Implementation Method 1

wireless power transmission system transmitting alternating-current power from a power transmission device to a power reception device

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

a resonance frequency of a coupler constituted of the first and the second electrode and the first inductor and a resonance frequency of a coupler constituted of the third and the fourth electrode and the second inductor are set to be substantially equal

Methodology Applied
Scientific EffectResonance: Resonance

Data Source

PatentEP2937972B1Wireless power transmission system
Publication Date: 2019.12.25 FURUKAWA ELECTRIC CO LTD
  • EP2937972B1 patent drawingFigure 1
  • EP2937972B1 patent drawingFigure 2
  • EP2937972B1 patent drawingFigure 3

AI summary

[OBJECT] There is provided a wireless power transmission system capable of transmitting power efficiently even when it is rotated. [ORGANIZATION] A power transmission device has a first and a second electrode (a center electrode 311 and an annular electrode 312) each having a rotationally symmetrical shape with respect to a common center axis, a first and a second connection line (connection lines 315, 316), and a first inductor (inductor 313, 314). A power reception device has a third and a fourth electrode (center electrode 321 and annular electrode 322) each having a rotationally symmetrical shape with respect to a common center axis, a third and a fourth connection line (connection lines 325, 326), and a second inductor. The electrodes of the power transmission device and the power reception device are disposed to oppose each other across a distance of λ/2π or less as a near field, and a resonance frequency of a coupler constituted of the first and the second electrode and the first inductor and a resonance frequency of a coupler constituted of the third and the fourth electrode and the second inductor (inductor 323, 324) are set to be substantially equal.