Insulated Wire Laminate Units for Partial Discharge Resistance

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Solution Overview

Problem

Existing insulated wires face challenges in maintaining high dielectric breakdown voltage and low dielectric constant, as increasing the thickness of the insulating layer for surge protection leads to size enlargement and insufficient interlayer adhesive force, while using resins low in dielectric constant results in poor electrical insulation and potential delamination.

Innovation Solution

An insulated wire with at least three laminate units, each comprising a layer low in dielectric constant and a layer high in dielectric constant, where the absolute difference between the dielectric constants of adjacent layers is 0.3 to 1.8, using resin compositions like polyetherimide, polyethersulfone, and polyamideimide to achieve high dielectric breakdown voltage without increasing the overall dielectric constant.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the thickness of the insulating layer is increased to prevent partial discharge deterioration, then the partial discharge resistance is improved, but the size of electrical equipments is enlarged and the space factor is lowered

Engineering Contradiction:
Improvepartial discharge resistanceVSAvoidsize of electrical equipments
Core Design Contradiction:
ReliabilityVSVolume of moving object

Solution Approach 1:

The patent applies composite materials by combining a polyamideimide resin layer (high dielectric breakdown voltage) with a fluorinated polyimide resin layer (low dielectric constant). This composite structure achieves both high partial discharge resistance and low dielectric constant without increasing overall insulating layer thickness, thus preventing equipment size enlargement while maintaining reliability.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent implements local quality by assigning different functional properties to different layers: the polyamideimide resin layer provides high dielectric breakdown voltage and adhesion, while the fluorinated polyimide resin layer provides low dielectric constant. This localized functional distribution optimizes overall performance without requiring uniform thickness increase throughout the insulating structure.

Inventive Principle:
Principle #3Local quality

2Reliability

If a polyimide resin with fluorine atom or perfluoroalkyl group is used to achieve low dielectric constant, then the dielectric constant is reduced, but the interlayer adhesive force is insufficient causing delamination

Engineering Contradiction:
Improvedielectric constantVSAvoidinterlayer adhesive force
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent uses composite materials where the polyamideimide resin layer provides strong interlayer adhesion and dielectric breakdown resistance, while the fluorinated polyimide resin layer contributes low dielectric constant. The combination ensures both low dielectric constant and sufficient adhesive force, preventing delamination issues.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent segments the insulating layer into two distinct functional layers: a polyamideimide resin layer for adhesion and dielectric strength, and a fluorinated polyimide resin layer for low dielectric constant. This segmentation allows each layer to specialize in its optimal function without compromising the other.

Inventive Principle:
Principle #1Segmentation

3Reliability

If the number of amido groups and imido groups in polyamideimide resin is reduced to achieve low dielectric constant, then the dielectric constant is reduced, but the adhesive force to conductor becomes insufficient

Engineering Contradiction:
Improvedielectric constantVSAvoidadhesive force to conductor
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent employs composite materials where the polyamideimide resin layer maintains sufficient amido and imido groups for strong conductor adhesion, while the fluorinated polyimide resin layer provides the low dielectric constant property. This composite approach decouples the adhesion function from the dielectric constant optimization.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent segments the adhesive function and dielectric constant optimization into separate layers: the polyamideimide resin layer retains high adhesive force through sufficient polar groups, while the fluorinated polyimide resin layer achieves low dielectric constant. This functional segmentation resolves the contradiction between adhesion and dielectric properties.

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 provides an insulated wire with excellent interlayer adhesiveness, high partial discharge resistance, and low dielectric constant, maintaining high dielectric breakdown voltage and electrical insulation properties while minimizing size and material costs.

Implementation Method 1

it becomes required in insulated wires to have minimized partial discharge deterioration due to the inverter surge

Methodology Applied
Scientific EffectPartial discharge: Townsend Discharge

Implementation Method 2

an insulating layer low in a dielectric constant and an insulating layer high in a dielectric constant are repeatedly formed multiple times on a conductor

Methodology Applied
Scientific EffectDielectric constant: Dielectric Permittivity

Implementation Method 3

an insulating layer is formed by repeatedly applying, on a conductor, a coating containing a solvent multiple times, followed by drying

Methodology Applied
Scientific EffectCoating: Coatings

Data Source

PatentEP2555204B1Insulated wire
Publication Date: 2018.02.14 FURUKAWA ELECTRIC CO LTD
  • EP2555204B1 patent drawingFigure 1~2(c)
  • EP2555204B1 patent drawing

AI summary

{Problems} To provide an insulated wire, which is high in a dielectric breakdown resistance even if insulating resin coatings are laminated, because the interlayer adhesiveness is excellent, and which is excellent in a partial discharge resistance, because the dielectric constant is low. {Means to solve} An insulated wire, having directly or indirectly on a conductor (1), at least two laminate units each formed by laminating an insulating layer (21,23) and an insulating layer (22, 24) higher in a dielectric constant than the insulating layer (21, 23), in this order from the conductor side.