Split-Core Coil Structure for Lower AC Resistance

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Solution Overview

Problem

Existing coil components experience significant power loss due to alternating-current resistance and fail to achieve sufficient quality factors, particularly at high frequencies and with large electric power applications.

Innovation Solution

A coil component structure featuring a core composed of linearly arranged split cores with non-magnetic intervening layers to reduce leakage magnetic flux, combined with a hollow cylindrical design and insulating coatings to minimize skin effect and core loss, allowing for reduced alternating-current resistance and enhanced quality factors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If a traditional solid core structure is used, then the magnetic flux path is continuous, but the alternating-current resistance increases and quality factor decreases due to skin effect and core loss

Engineering Contradiction:
Improvealternating-current resistanceVSAvoidquality factor
Core Design Contradiction:
Loss of energyVSReliability

Solution Approach 1:

The core is divided into multiple split cores (first split core, second split core, third split core, fourth split core) arranged linearly with non-magnetic intervening layers between them. This segmentation breaks the continuous magnetic flux path into discrete segments, reducing the skin effect and core loss that occur in traditional solid core structures, thereby reducing alternating-current resistance and improving quality factor.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Non-magnetic intervening layers are strategically placed between adjacent split cores at specific locations where magnetic flux leakage occurs. These intervening layers have different magnetic properties (non-magnetic) compared to the split cores, creating local variations in magnetic flux distribution that reduce leakage and improve overall efficiency.

Inventive Principle:
Principle #3Local quality

2Loss of energy

If split cores with non-magnetic intervening layers are used, then leakage magnetic flux is reduced and alternating-current resistance decreases, but the core structure becomes more complex

Engineering Contradiction:
Improveleakage magnetic fluxVSAvoidcore structure
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The core is divided into multiple split cores (first split core, second split core, third split core, fourth split core) arranged linearly with non-magnetic intervening layers between them. This segmentation breaks the continuous magnetic flux path into discrete segments, reducing the skin effect and core loss that occur in traditional solid core structures, thereby reducing alternating-current resistance and improving quality factor.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Multiple split cores are combined in a linear arrangement to form a unified core structure that functions as a single magnetic circuit element. The individual split cores are positioned and connected through the bobbin structure to create an integrated assembly that achieves the desired magnetic flux control while maintaining structural coherence.

Inventive Principle:
Principle #5Merging (Combining)

3Reliability

If a hollow cylindrical core design with insulating coatings is used, then skin effect and core loss are minimized, but manufacturing complexity increases

Engineering Contradiction:
Improvequality factorVSAvoidcore manufacturing
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

Insulating coatings are applied to the hollow cylindrical core structure at specific locations to provide electrical isolation where needed. This localized application of insulating properties allows the core to maintain its hollow cylindrical geometry while providing necessary electrical insulation to reduce skin effect and core loss, balancing performance requirements with manufacturing feasibility.

Inventive Principle:
Principle #3Local quality

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 proposed coil component design effectively reduces alternating-current resistance and achieves high-quality factors, making it suitable for high-frequency, high-power applications like field coupling non-contact power supply systems with low loss and excellent resonance performance.

Implementation Method 1

An intervening layer made out of a non-magnetic material is disposed between split cores adjacent to each other of the plurality of split cores. This structure reduces leakage magnetic flux and hence makes it possible to reduce alternating-current resistance.

Methodology Applied
Scientific EffectMagnetic flux leakage reduction: Magnetic Field

Implementation Method 2

insulating coatings to minimize skin effect and core loss, allowing for reduced alternating-current resistance and enhanced quality factors

Methodology Applied
Scientific EffectSkin effect: Skin Effect

Implementation Method 3

a coil wound around the core 30. The coil component according to the present invention can be used, for example, as a resonance coil for a field coupling non-contact power supply system

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP3358580B1Coil component
Publication Date: 2024.12.04 SUMIDA CORP
  • EP3358580B1 patent drawingFigure 1
  • EP3358580B1 patent drawingFigure 2
  • EP3358580B1 patent drawingFigure 3

AI summary

A coil component includes a core (30); and a coil wound around the core (30), in which the core (30) is configured to include plural split cores (31) arranged linearly alongside each other in an axial-center direction of the coil, and an intervening layer made out of a non-magnetic material (for example, comprised of an insulating coating (35)) is disposed between split cores (31) adjacent to each other of the plural split cores (31).