Adjustable Resistance Corona Shielding via SiC Doping

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Solution Overview

Problem

Existing corona protection systems face challenges in achieving precise, cost-effective, and stable resistance adjustment for end corona protection due to complex doping processes and instability in particle mixtures with different sizes.

Innovation Solution

A corona shielding material comprising a mixture of doped and undoped SiC particles with the same particle size distribution, allowing resistance adjustment through varying concentrations of doped particles, embedded in a polymeric matrix, which can include silicon carbide and carbon black, to achieve tailored electrical resistance for field control.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If different particle sizes are used to achieve desired resistance, then resistance adjustment is possible, but the mixture is unstable for storage due to segregation

Engineering Contradiction:
Improveresistance adjustmentVSAvoidstorage stability
Core Design Contradiction:
Manufacturing precisionVSStability of the object's composition

Solution Approach 1:

The patent changes the parameter of particle size from variable (different sizes mixed) to fixed (single size fraction), and instead adjusts resistance by changing the concentration of doped particles within that fixed size distribution. This resolves the contradiction by maintaining compositional stability during storage while still enabling precise resistance adjustment through doping concentration control.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent segments the resistance adjustment function into two independent components: particle size (fixed for stability) and doping concentration (variable for resistance control). By separating these functions, the system achieves both storage stability and adjustable resistance without the segregation problems of mixed particle sizes.

Inventive Principle:
Principle #1Segmentation

2Manufacturing precision

If complex doping processes are used to adjust resistance, then precise resistance control is achieved, but manufacturing complexity and cost increase

Engineering Contradiction:
Improveresistance control precisionVSAvoiddoping process complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent simplifies the doping process by changing from complex multi-step doping procedures to a simpler single-step doping approach. Resistance precision is maintained by controlling the concentration of doped particles in the mixture, rather than through complex process parameters, thereby reducing manufacturing complexity while preserving control precision.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses a composite filler system combining doped and undoped SiC particles in a single matrix. This composite approach allows resistance adjustment through simple compositional control (ratio of doped to undoped particles) rather than complex processing, reducing manufacturing complexity while maintaining precise resistance control.

Inventive Principle:
Principle #40Composite materials

3Adaptability or versatility

If multiple fillers with different fraction sizes and doping levels are used, then targeted resistance layers can be created, but storage and mixing complexity increase significantly

Engineering Contradiction:
Improveresistance layer customizationVSAvoidstorage and mixing ease
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The patent changes the approach from varying particle size fractions to using a single fraction size with variable doping levels. This maintains the ability to create targeted resistance layers through compositional control while dramatically simplifying storage and mixing operations, as no fractionation or complex blending is required.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent makes a single particle size fraction universal for all resistance requirements by adjusting only the doping concentration. This eliminates the need for multiple specialized fillers with different sizes, allowing one base material to serve all resistance needs through simple compositional adjustment, thereby simplifying storage and handling.

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

This approach enables precise adjustment of electrical resistance over a wide range, ensuring stability and cost-effectiveness, allowing for reproducible resistance layers that can be stored indefinitely without segregation, effectively addressing the limitations of prior systems.

Implementation Method 1

the filler is a mixture of doped and undoped SiC particles of the same particle size distribution and the resistance in the flame-retardant material is adjustable by the amount of doped particles in the mixture

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentEP3218908B1Corona shielding material with an adjustable resistance
Publication Date: 2020.03.25 SIEMENS ENERGY GLOBAL GMBH & CO KG
  • EP3218908B1 patent drawingFigure 1
  • EP3218908B1 patent drawingFigure 2
  • EP3218908B1 patent drawingFigure 3

AI summary

The invention relates to a corona shielding material, in particular for a corona shielding system, comprising an outer corona shielding system (EGS). According to the invention, a corona shielding material is presented, in which the filler is present in a single particle size fraction and embedded in a matrix, and nevertheless the setting of a desired electrical resistance can be achieved.