Stator Neutral Busbar Sealing for Accurate Temperature Sensing
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Solution Overview
Problem
The existing rotating electrical machines face challenges in accurately measuring the temperature of the stator due to the low thermal resistance of the resinous seal, which leads to heat dissipation from the neutral busbar, resulting in a lower measured temperature than the actual stator temperature.
Innovation Solution
The stator design incorporates a resinous seal with bubbles formed in the insulating resin around the neutral busbar to increase thermal resistance, reducing heat dissipation and minimizing the risk of cracks, thereby allowing the temperature sensor to accurately measure the stator temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the resinous seal is made with low thermal resistance to provide good thermal conduction, then heat dissipation is improved, but the temperature measurement accuracy deteriorates because the measured temperature becomes lower than the actual stator temperature
Solution Approach 1:
The insulating resin is designed with non-uniform thermal resistance distribution: the first region (surrounding coil ends) has lower thermal resistance for heat dissipation, while the second region (surrounding neutral busbar) has higher thermal resistance to maintain temperature measurement accuracy. This local differentiation resolves the contradiction by providing good heat dissipation where needed while preserving temperature accuracy where measurement occurs.
Solution Approach 2:
The insulating resin is divided into multiple regions with different thermal resistance characteristics. The first region provides thermal conduction for heat dissipation, while the second region provides thermal insulation for accurate temperature measurement. This segmentation allows the system to simultaneously achieve both heat dissipation and measurement accuracy.
2Reliability
If the insulating resin is made dense without bubbles to provide good electrical insulation, then insulation performance is improved, but thermal resistance decreases causing excessive heat dissipation and inaccurate temperature measurement
Solution Approach 1:
Bubbles are strategically introduced only in the second region surrounding the neutral busbar, while the first region surrounding coil ends maintains dense structure. This local differentiation allows the second region to have high thermal resistance for accurate temperature measurement while the first region provides good electrical insulation through its dense structure.
Solution Approach 2:
Bubbles act as thermal insulation intermediaries in the second region, increasing thermal resistance between the neutral busbar and the external environment. This allows the temperature sensor to measure the neutral busbar temperature more accurately without compromising overall electrical insulation, as the bubbles are confined to a specific region.
3Measurement precision
If the insulating resin is made with high thermal resistance to prevent heat dissipation, then temperature measurement accuracy is improved, but heat dissipation capability deteriorates leading to overheating
Solution Approach 1:
The insulating resin is segmented into a first region with lower thermal resistance for heat dissipation and a second region with higher thermal resistance for temperature measurement accuracy. This segmentation allows the system to simultaneously achieve both heat dissipation capability and accurate temperature measurement by assigning different thermal resistance characteristics to different functional regions.
Solution Approach 2:
Different thermal resistance properties are assigned to different regions: the first region surrounding coil ends has lower thermal resistance for heat dissipation, while the second region surrounding the neutral busbar has higher thermal resistance to maintain temperature accuracy. This local quality differentiation resolves the contradiction between heat dissipation and measurement accuracy.
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 configuration with bubbles in the resinous seal enhances the accuracy of temperature measurement by maintaining the neutral busbar's temperature, ensuring the temperature sensor provides a more precise reading of the stator's temperature.
Implementation Method 1
the thermal resistance of a surrounding portion of the insulating resin, which is located around the neutral busbar, to be higher, making it possible to reduce heat dissipation from the neutral busbar through the insulating resin of the resinous seal
Data Source
AI summary
In a stator for a rotating electrical machine, a stator core, and a stator winding are provided. The stator winding is located in or around the stator core and has a coil end exposed outside a corresponding end of the stator core. A neutral busbar is connected to the coil end of the stator winding, and a temperature sensor is mounted to the neutral busbar. A resinous seal includes an insulating resin, and the insulating resin of the resinous seal is arranged to cover an axial end portion of the coil end and the neutral busbar. The resinous seal is configured to have bubbles formed in the insulating resin. The bubbles are located around the neutral busbar.