Coil Device Inductance Adjustment via Eddy Current Interruption

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Solution Overview

Problem

Existing wireless power transfer systems face challenges in maintaining optimal inductance values due to environmental variations and manufacturing inconsistencies, which affect power transmission efficiency and require complex mechanisms to adjust inductance without increasing device size.

Innovation Solution

A coil device with a non-magnetic member featuring an eddy current interrupter, allowing for adjustable inductance by changing the path of eddy currents through moving mechanisms, thereby optimizing inductance without physical changes to the coil, using slits or holes to divert eddy currents and maintain desired inductance values.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a magnetic-field shield is moved to change inductance, then the inductance can be adjusted, but the device size increases and manufacturing complexity increases

Engineering Contradiction:
Improveinductance adjustabilityVSAvoiddevice size
Core Design Contradiction:
Adaptability or versatilityVSVolume of stationary object

Solution Approach 1:

The patent changes the inductance by moving the non-magnetic member to different positions relative to the coil, thereby changing the eddy current path length and resistance. This allows inductance adjustment without adding magnetic shields or complex mechanical structures, maintaining compact device size while achieving the desired inductance variability.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent extracts the inductance adjustment function from traditional magnetic shield mechanisms and implements it through a non-magnetic member that utilizes eddy currents. By removing the need for magnetic materials and complex shielding structures, the device size is reduced while maintaining the ability to adjust inductance through positional changes of the non-magnetic member.

Inventive Principle:
Principle #2Taking out (Extraction)

2Adaptability or versatility

If inductance is adjusted by changing coil structure, then the inductance can be optimized, but the manufacturing precision requirements increase and device complexity increases

Engineering Contradiction:
Improveinductance optimizationVSAvoidcoil structure precision
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

Instead of changing the coil structure to adjust inductance, the patent changes the magnetic environment around the coil by positioning a non-magnetic member at different distances. This approach allows inductance optimization without modifying the coil winding structure, thereby reducing manufacturing precision requirements and simplifying the overall device structure.

Inventive Principle:
Principle #35Parameter changes

3Adaptability or versatility

If multiple components are used to adjust inductance, then the inductance control is more precise, but the device complexity and manufacturing cost increase

Engineering Contradiction:
Improveinductance control precisionVSAvoidnumber of components
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The non-magnetic member serves multiple functions: it provides structural support, guides the magnetic field, and enables inductance adjustment through positional changes. By combining these functions into a single component, the patent reduces the number of parts needed while maintaining precise inductance control, thereby simplifying the device structure and reducing manufacturing complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 effectively adjusts inductance to achieve desired values while minimizing device size, enhancing power transfer efficiency and reducing manufacturing costs by allowing for easy adjustment of inductance using interchangeable non-magnetic members.

Implementation Method 1

a non-magnetic member 56a, 56b having an eddy current interrupter 50B is provided between the coil portion 15B and the base 54

Methodology Applied
Scientific EffectEddy current: Eddy Currents

Implementation Method 2

implements wireless power transmission using magnetic coupling between coils such as an electromagnetic induction scheme

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP3163588B1Coil device and inductance-changing mechanism
Publication Date: 2020.08.05 IHI CORP
  • EP3163588B1 patent drawingFigure 1
  • EP3163588B1 patent drawingFigure 2A~2B
  • EP3163588B1 patent drawingFigure 3A~3B

AI summary

A coil device includes a first coil portion which faces a second coil portion of another coil device and has a conductive wire, and at least one non-magnetic member disposed on an opposite side from a side facing the second coil portion. The non-magnetic member includes an eddy current interrupter for changing a state of an eddy current formed in the non-magnetic member by interrupting a portion of the eddy current.