Stator Insulation Paper Coating for Compact Creepage Resistance
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Solution Overview
Problem
Existing electric machines for motor vehicles face challenges in reducing installation space while maintaining electrical safety, particularly due to higher power densities leading to increased currents and voltages, which affect the design of insulation paper and creepage currents.
Innovation Solution
A stator design with an additional layer on the insulation paper surface within the stator groove, enhancing creepage resistance, allowing for a reduced axial extent of the insulation paper and thus minimizing installation space and material usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the insulation paper is extended axially to ensure electrical safety and prevent creepage currents, then the electrical insulation reliability is improved, but the installation space and device dimensions increase
Solution Approach 1:
The patent applies a hydrophobic additional layer specifically to the axial protruding portions of the insulation paper where creepage currents are most likely to occur, rather than treating the entire insulation paper uniformly. This localized treatment provides enhanced creepage resistance exactly where needed (at the axial ends and surfaces exposed to potential contamination) while avoiding unnecessary extension of the insulation paper's axial length, thus resolving the contradiction between reliability and dimensions.
Solution Approach 2:
The patent combines the base insulation paper material with a hydrophobic additional layer to create a composite insulation structure. The base paper provides fundamental electrical insulation, while the hydrophobic coating layer provides enhanced creepage resistance by repelling moisture and preventing conductive paths. This composite approach achieves superior electrical safety without requiring increased axial dimensions of the insulation paper.
2Length of moving object
If the insulation paper axial extent is reduced to minimize installation space, then the device compactness is improved, but the creepage resistance and electrical safety are compromised
Solution Approach 1:
The patent changes the surface property parameter of the insulation paper by applying a hydrophobic coating layer, which fundamentally alters how the surface interacts with moisture and contaminants. This parameter change (from hydrophilic to hydrophobic surface) provides enhanced creepage resistance without requiring increased axial length of the insulation paper, thus resolving the contradiction between compactness and electrical safety.
3Ease of manufacture
If a standard insulation paper surface is used, then the manufacturing simplicity is maintained, but the creepage resistance is insufficient for high power density applications
Solution Approach 1:
The patent creates a composite structure by adding a hydrophobic layer to the insulation paper, which can be applied through established coating techniques. This approach maintains relative manufacturing simplicity while dramatically improving creepage resistance, making it suitable for high power density applications where standard insulation papers would be insufficient.
Solution Approach 2:
The patent modifies the surface parameter of the insulation paper through hydrophobic coating, transforming it from a standard surface with adequate creepage resistance to an enhanced surface with superior creepage resistance. This parameter change achieves the required reliability for high power density applications while maintaining manufacturing feasibility through conventional coating 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
The additional layer significantly improves creepage resistance, reducing the axial installation space requirement and production costs while ensuring electrical safety and reliability, enabling a compact and safe electric machine.
Implementation Method 1
the insulation paper is provided with an additional layer on a surface of the insulation paper for providing a higher creepage resistance compared to the surface of the insulation paper without the additional layer
Data Source
AI summary
A stator for an electric machine provided for purely electrically driving a motor vehicle is provided with a stator body forming stator grooves, a stator winding through which current can flow, which engages in the respective stator groove and axially protrudes from the stator groove, for forming an electromagnetic rotating field and an insulation paper, which is provided in the stator groove between the stator winding and the stator body, for electrically insulating the stator winding from the stator body, wherein the insulation paper protrudes from the stator groove, wherein the insulation paper is provided with an additional layer on the surface thereof for providing a higher creepage resistance compared to the surface of the insulation paper without the additional layer.