Conductive Shielded Winding Insulation for Partial Discharge Control
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Solution Overview
Problem
Conventional electric machines, particularly those used in high-altitude aerospace environments, face limitations due to partial discharge issues, which are exacerbated by lower partial discharge inception and extinction voltages, leading to reduced efficiency and increased machine size, and existing insulation materials are limited by temperature ratings, restricting operational performance.
Innovation Solution
The implementation of a conductor core with an insulation layer surrounded by a conductive shield layer, where the shield layer includes an insulative carrier with a thermal rating greater than 180°C and a conductive layer with a surface resistivity between 1.5 and 10 ohms per square, circumferentially surrounding the insulation layer, enhances electrical ratings and prevents partial discharge without increasing insulation thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional insulation materials are used in high-altitude aerospace environments, then the machine can operate at lower voltages, but partial discharge issues occur due to lower partial discharge inception and extinction voltages
Solution Approach 1:
The patent applies composite materials by combining an insulation layer with a conductive shield layer having specific surface resistivity characteristics (10^6 to 10^12 ohms per square). This composite structure prevents partial discharge while enabling higher voltage operation, resolving the contradiction between reliability and power rating in high-altitude environments where conventional single-material insulation fails.
Solution Approach 2:
The patent changes the electrical parameters of the insulation system by introducing a conductive shield layer with controlled surface resistivity. This parameter modification raises the partial discharge inception voltage and improves extinction characteristics, allowing the machine to operate reliably at higher voltages in high-altitude aerospace environments where conventional insulation materials would fail.
2Reliability
If insulation thickness is increased to prevent partial discharge, then partial discharge prevention improves, but machine size increases
Solution Approach 1:
Instead of increasing insulation thickness, the patent uses a composite structure with a thin insulation layer combined with a conductive shield layer having specific surface resistivity characteristics. This approach prevents partial discharge through electrical field control rather than physical thickness, avoiding machine size enlargement while maintaining reliability.
Solution Approach 2:
The patent employs a thin conductive shield layer with controlled surface resistivity as a flexible protective barrier. This thin film structure provides effective partial discharge prevention without requiring thick insulation, thereby preventing machine size increase while maintaining reliability in high-voltage aerospace applications.
3Ease of manufacture
If existing insulation materials are used, then manufacturing is simple, but temperature ratings are limited restricting operational performance
Solution Approach 1:
The patent combines conventional insulation materials with a conductive shield layer having specific surface resistivity characteristics. This composite approach maintains the ease of manufacturing simple insulation structures while adding the temperature performance benefits of conductive materials, enabling higher temperature ratings without complicating the manufacturing process.
Solution Approach 2:
The patent merges conventional insulation materials with conductive shield layers in a single integrated structure. This combination unifies the manufacturing simplicity of traditional insulation with the high-temperature performance of conductive materials, allowing the machine to operate at higher temperatures without requiring separate manufacturing processes.
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 configuration allows for higher voltage operation at high altitudes, improving power density and temperature ratings while reducing the risk of partial discharge, enabling efficient operation without enlarging the machine size.
Implementation Method 1
a conductive layer having a surface resistivity between 1.5 and 10 ohms per square disposed on the insulative carrier
Implementation Method 2
a conductive shield layer overlying the insulation layer, the conductive shield layer comprising: an insulative carrier formed from a material having a thermal rating greater than 180°C
Data Source
AI summary
An electric winding assembly includes a conductor core having a first end and an opposing second end, an insulation layer overlying the conductor core, and a conductive shield layer overlying the insulation layer. The conductive shield layer includes an insulative carrier circumferentially surrounding the insulation layer and a conductive layer disposed on the insulative carrier, the insulative carrier formed from a material having a thermal rating greater than 180° C., the conductive shield layer having a surface resistivity between 1.5 and 10 ohms per square.