Electric Machine Cooling via Segmented Annuli
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing cooling methods for electric machines, such as spraying coolant around the stator, result in elevated coolant temperatures, reducing the effectiveness of heat extraction from the end turns due to the coolant's increased temperature as it flows circumferentially.
Innovation Solution
An electric machine module with a coolant transport network that includes annuli and passages within the module housing, allowing pressurized coolant to be directed axially and radially onto the stator and rotor assemblies through apertures, enhancing heat extraction by maintaining a lower coolant temperature and increasing contact with heat-generating components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If coolant is sprayed from the cooling jacket directly onto end turns of the stator, then cooling of the end turns is improved, but the coolant temperature is elevated which reduces the level of heat extracted from the end turns
Solution Approach 1:
The cooling system is segmented into multiple independent cooling circuits: a first cooling circuit for the stator core and a second cooling circuit for the end turns. This segmentation allows each circuit to operate with optimally cooled coolant, preventing the temperature degradation that occurs in a single circumferential loop.
Solution Approach 2:
Coolant is pre-cooled in the first cooling circuit before being directed to the end turns through the second cooling circuit. This preliminary cooling action ensures that the coolant maintains a lower temperature when it reaches the end turns, maximizing heat extraction effectiveness.
2Reliability
If coolant flows circumferentially around the cooling jacket, then the stator is cooled, but the coolant temperature increases reducing cooling effectiveness at the end turns
Solution Approach 1:
The single circumferential cooling jacket is segmented into two separate cooling circuits with independent coolant flow paths. The first circuit cools the stator core while the second circuit independently cools the end turns, preventing thermal cross-contamination and maintaining optimal coolant temperatures at both locations.
Solution Approach 2:
A thermal coupling mechanism acts as an intermediary between the first and second cooling circuits, allowing heat transfer from the stator core to the coolant in the first circuit, which then transfers cooled coolant to the second circuit for end turn cooling, optimizing the thermal management of both components.
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 described configuration effectively increases the cooling efficiency of the electric machine by ensuring a consistent flow of cooler coolant to the stator and rotor assemblies, thereby improving the heat removal process and extending the machine's performance and lifespan.
Implementation Method 1
The coolant extracts at least a portion of the heat produced by a stator
Implementation Method 2
passing a coolant around an outer perimeter of the electric machine inside of a cooling jacket
Data Source
AI summary
Embodiments of the invention provide an electric machine module including a module housing, which can at least partially define a machine cavity. In some embodiments, an electric machine can include a stator assembly and a rotor assembly and can be positioned in the machine cavity. In some embodiments, the module housing can include a coolant transport network, which can include at least one passage in fluid communication with at least one first annulus and at least one second annulus. In some embodiments, the first annulus can be substantially axially adjacent to an axial end of the stator assembly and the second annulus can be substantially axially adjacent to an axial end of the rotor assembly. In some embodiments, the annuli can include a plurality of annulus apertures.