Hairpin Stator Insulation Layout for Partial Discharge Suppression
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Solution Overview
Problem
Conventional stators in electric rotating machines face issues with partial discharge due to high voltage surges, reduced output power due to decreased fill factor, and increased production costs from using different insulating materials, as well as magnetic flux saturation.
Innovation Solution
A stator design with first hairpins having better electrical insulation performance than second hairpins, arranged in sections with higher voltage distribution, uses a coating layer with lower specific inductive capacity to reduce partial discharge and production costs, while maintaining conductor space factor and tooth width.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the thickness of coating layer of hairpin is increased to ensure insulation performance against high voltage surge, then partial discharge is suppressed, but the space factor or fill factor of conductor with respect to slot cross sectional area decreases, reducing output power
Solution Approach 1:
The patent applies different coating layer thicknesses to different regions of the hairpin conductor. The first coating layer at the tip has a greater thickness than the second coating layer at the body portion. This local differentiation allows enhanced insulation where voltage surge and partial discharge risk is highest (the tip region) while maintaining larger conductor cross-section in the body portion to preserve fill factor and output power.
2Power
If the thickness of coating layer is entirely decreased to increase space factor of conductor, then output power is enhanced, but insulation performance in crossing region where potential difference is generated between phases is insufficient
Solution Approach 1:
The patent implements variable coating thickness where the first coating layer at the tip has greater thickness for enhanced insulation in regions experiencing high voltage stress and phase potential differences, while the second coating layer at the body portion has reduced thickness to maximize conductor space factor and output power.
3Strength
If outer side and inner side of hairpin are coated with different insulating materials to ensure durability against compressive and tensile forces, then durability is improved, but production time and cost increase significantly
Solution Approach 1:
The patent applies different coating layers to different spatial regions of the hairpin conductor - the first coating layer at the tip and the second coating layer at the body portion. This regional differentiation provides targeted protection against different stress conditions while maintaining a relatively simple single-piece coating structure that is more efficient to manufacture than completely separate coatings on opposite sides.
Solution Approach 2:
The coating structure is segmented into two distinct coating layers applied to different regions of the hairpin, allowing optimized protection for each region while maintaining manufacturing efficiency through a unified coating process approach.
4Reliability
If uniform thick coating layer is applied to entire hairpin to ensure insulation performance, then partial discharge is suppressed, but the fill factor of conductor decreases significantly, reducing output power
Solution Approach 1:
The patent implements non-uniform coating thickness distribution where the first coating layer at the tip has greater thickness for enhanced insulation performance in high-voltage-stress regions, while the second coating layer at the body portion has reduced thickness to maximize conductor cross-section and fill factor, thereby maintaining output power.
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 design effectively suppresses partial discharge, enhances output power, reduces production costs, and prevents magnetic flux saturation by optimizing insulation and conductor arrangement.
Implementation Method 1
a coating layer formed to surround an outer surface of the conductor, the stator coil includes a first hairpin placed in a preset first section from an end to which power is to be input and a second hairpin placed in a second section after the first section, and the first hairpin has better electrical insulation performance than the second hairpin
Data Source
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AI summary
The present disclosure relates to a stator for an electric rotating machine, and the stator may include a stator core having teeth and slots; and a stator coil formed by connecting a plurality of hairpins to be inserted into the slots in a predetermined pattern, wherein each of the plurality of hairpins includes a conductor and a coating layer formed to surround an outer surface of the conductor, and the stator coil includues a first hairpin placed in a preset first section from an end to which power is to be input and a second hairpin placed in a second section after the first section, and the first hairpin has better insulation performance than the second hairpin. Thus, insulation performance may be ensured to suppress occurrence of partial discharge.