Stator Cooling via Transverse Fluid Flow
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Solution Overview
Problem
Electrical machines, such as motors and generators, generate heat due to energy conversion between mechanical and electrical domains, which can lead to inefficiencies and component degradation, and existing cooling systems may not effectively manage this heat, especially at high operational speeds.
Innovation Solution
The electrical machine incorporates a cooling system where cooling fluid is communicated transversely across the stator, with multiple inlets and outlets radially positioned outside the stator's interior surface, and liquid cooling jackets circulate fluid along serpentine paths around the stator to efficiently dissipate heat, including through an air gap between the stator and rotor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If cooling fluid is communicated through the stator, then heat dissipation is improved, but device complexity increases
Solution Approach 1:
The cooling system is segmented into multiple independent cooling zones: end-turn cooling channels at the stator ends, axial cooling channels through the stator core, and radial cooling channels through the air gap. Each zone has dedicated inlet and outlet ports, allowing independent cooling fluid flow paths that target specific heat generation regions separately, thereby improving heat dissipation without requiring a monolithic complex cooling structure
Solution Approach 2:
The cooling fluid serves multiple functions simultaneously: it cools the end turns through external channels, cools the stator core through axial channels, and cools the air gap through radial channels. A single cooling fluid circulation system performs multiple cooling tasks that would otherwise require separate systems, reducing overall device complexity while maintaining effective heat dissipation across all stator regions
2Temperature
If multiple cooling inlets and outlets are added, then cooling effectiveness is improved, but manufacturing complexity increases
Solution Approach 1:
Multiple cooling functions are merged into integrated cooling structures. The end-turn cooling channels are combined with the stator yoke structure, axial cooling channels are integrated into the stator core laminations, and radial cooling channels are merged with the air gap region. This consolidation reduces the number of separate manufacturing components while achieving multi-zone cooling through coordinated fluid flow paths
3Temperature
If cooling fluid flows transverse across the stator, then heat transfer efficiency is improved, but fluid flow complexity increases
Solution Approach 1:
The cooling fluid flow direction is optimized for each local region: transverse flow across end turns at the stator ends, axial flow through the stator core, and radial flow through the air gap. Each region receives cooling fluid in the direction that maximizes heat transfer efficiency for that specific location, with inlet and outlet ports positioned to create appropriate flow patterns without requiring complex overall fluid distribution mechanisms
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 cooling system effectively manages heat generation in electrical machines, maintaining efficiency and extending component lifespan, even at high speeds exceeding 3,600 rotations per minute, by ensuring thorough heat transfer and dissipation.
Implementation Method 1
cooling fluid is communicated through a volume external to the stator substantially transverse across one or both ends of the stator, and/or cooling fluid is communicated through a volume internal to the stator in an axial direction toward one or both ends of the stator
Implementation Method 2
cooling fluid is communicated through a volume internal to the stator in an axial direction toward one or both ends of the stator
Data Source
AI summary
An electrical machine includes a stator and a rotor disposed in a housing of the electrical machine. The stator includes windings having a first set of end turns at a first end of the stator and having a second set of end turns at a second, opposing end of the stator. The stator has a substantially tubular shape and an interior lateral surface. The rotor extends through the interior of the stator. A flow inlet into a volume in the housing about the first end turns is located radially outside of the interior lateral surface of the stator. A flow outlet from the volume in the housing about the first end turns is located radially outside of the interior lateral surface. The inlet and the outlet are cooperatively arranged to communicate a flow of fluid substantially transverse across the first end of the stator.