Multilayer Coil Asymmetry Parasitic Capacitance Balance

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Solution Overview

Problem

Existing contactless power transmission coils with double layered structures face issues with parasitic capacitance imbalance, leading to increased voltage to ground on metallic plates, and require improved productivity in multilayered configurations.

Innovation Solution

A conductive coil with a multilayered structure where winding wire portions in each layer are dispersed and separated by insulating members, with each layer's wire ends positioned to prevent bias and excess pressure, allowing for balanced parasitic capacitance and efficient parallel winding processes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If a double layered coil structure is used to reduce coil size, then the coil size is reduced, but parasitic capacitance imbalance occurs leading to increased voltage to ground on metallic plates

Engineering Contradiction:
Improvecoil sizeVSAvoidparasitic capacitance balance
Core Design Contradiction:
Volume of moving objectVSReliability

Solution Approach 1:

The patent applies asymmetry by intentionally creating different winding directions in the first and second layers. The first layer winds in one direction while the second layer winds in the opposite direction, which asymmetrically distributes the parasitic capacitance to achieve balance overall. This resolves the contradiction by using asymmetric local structures to achieve symmetric global performance in terms of capacitance balance.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The patent applies inversion by reversing the winding direction in the second layer compared to the first layer. Instead of both layers winding in the same direction, the second layer winds in the opposite direction, which inverts the capacitance distribution pattern and achieves balance between the two layers, preventing voltage imbalance on the metallic plate.

Inventive Principle:
Principle #13The other way round (Inversion)

2Volume of moving object

If winding wire portions in adjacent layers are placed close together to reduce coil volume, then the coil volume is reduced, but loss due to closing effect increases

Engineering Contradiction:
Improvecoil volumeVSAvoidclosing effect loss
Core Design Contradiction:
Volume of moving objectVSLoss of energy

Solution Approach 1:

The patent applies the intermediary principle by introducing an insulating member between the winding wire portions of adjacent layers. This insulating member acts as a mediator that physically separates the conductive elements, preventing the closing effect while maintaining the compact multilayered structure. The insulating member allows the layers to be close together for volume reduction without causing energy loss.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Volume of moving object

If spiral coils in the first and second layers are connected in series to reduce size, then the coil size is reduced, but productivity decreases due to sequential winding requirements

Engineering Contradiction:
Improvecoil sizeVSAvoidwinding production efficiency
Core Design Contradiction:
Volume of moving objectVSProductivity

Solution Approach 1:

The patent applies segmentation by dividing the coil into two separate layers with distinct winding processes. Each layer can be wound independently and simultaneously in different locations, then connected through insulating members. This segmentation enables parallel production of multiple coil sections, significantly improving productivity while maintaining the reduced size benefits of the multilayered structure.

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 solution achieves a uniform distribution of parasitic capacitance, preventing voltage imbalances and enabling effective production of multilayered coils with improved productivity and reduced losses.

Implementation Method 1

the winding wire portions in the adjacent upper and lower layers face to each other through an insulating member

Methodology Applied
Scientific EffectElectrical insulation: Dielectric

Implementation Method 2

a parasitic capacitance is generated between the conductor of the coil and the metallic plate

Methodology Applied
Scientific EffectParasitic capacitance: Parasitic Capacitance

Data Source

PatentEP2958119B1Coil
Publication Date: 2021.11.03 TDK CORP
  • EP2958119B1 patent drawingFigure 1~2
  • EP2958119B1 patent drawingFigure 3~5
  • EP2958119B1 patent drawingFigure 6~8

AI summary

The present invention provides a coil which maintains a balance of a parasitic capacitance and has a structure that can be multilayered. The coil is a coil with a stacked structure which includes winding wire portions formed of a wire wound for several turns in a plane in each layer, wherein the winding wire portions 2a and 2b in each layer include a first winding portion formed by performing a single turn of winding in each layer in a same winding direction from a bottom layer to an uppermost layer, and a second winding portion formed by performing a single turn of winding in each layer in a same winding direction from the uppermost layer to the bottom layer, and the winding directions of the first winding portion and the second winding portion are identical to each other and the first winding portion and the second winding portion are joined in the uppermost layer or the bottom layer.