Integral Stator Cooling via Interconnected Axial Radial Ducts
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Solution Overview
Problem
Current cooling methods for electrical machines, such as air-cooled and liquid-cooled systems, are inefficient in distributing heat across the stator stack, leading to hot spots and reduced life expectancy due to temperature-dependent winding resistance, and they often require complex cooling schemes that compromise electromagnetic functionality and structural integrity.
Innovation Solution
A laminated stator stack design incorporating interconnected axial and radial coolant ducts within the stator teeth, forming a predominantly closed flow path, which enhances heat exchange and cooling efficiency while maintaining electromagnetic functionality by strategically placing radial ducts to reduce thermal distance to high-loss sections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If air-cooled or liquid-cooled systems are used with axial vents or slot cooling, then cooling efficiency is improved, but device complexity and structural compromise increase
Solution Approach 1:
The patent merges the cooling duct system directly into the stator stack structure by integrating axial coolant ducts in the yoke region with radial coolant ducts in the teeth regions. This combination creates a unified cooling system that eliminates the need for separate cooling schemes, thereby reducing device complexity while maintaining effective cooling of both yoke and tooth regions
Solution Approach 2:
The stator stack structure serves multiple functions: it provides the electromagnetic core function while simultaneously housing the integrated coolant ducts for cooling. The yoke region contains axial ducts for coolant flow, and the teeth regions contain radial ducts, making the stator stack a multi-functional component that combines structural, electromagnetic, and thermal management roles
2Temperature
If cooling ducts are added to the stator stack, then heat exchange area is increased, but electromagnetic functionality is reduced
Solution Approach 1:
The patent applies local quality by placing axial coolant ducts specifically in the yoke region and radial coolant ducts specifically in the teeth regions. This localized approach ensures that cooling channels are positioned where they are most needed for heat removal, while minimizing the impact on electromagnetic functionality in other areas of the stator stack
Solution Approach 2:
The patent utilizes the radial dimension by extending coolant ducts into the teeth regions from the yoke. This three-dimensional arrangement of cooling ducts (axial in yoke, radial in teeth) maximizes heat exchange area without significantly compromising the electromagnetic functionality, as the ducts are strategically positioned to remove heat from high-loss regions
3Ease of manufacture
If uniform cooling is applied across the stator stack, then manufacturing simplicity is maintained, but hot spots develop due to non-uniform heat generation
Solution Approach 1:
The patent implements non-uniform cooling by providing axial coolant ducts in the yoke region and radial coolant ducts in the teeth regions. This localized cooling approach matches the heat generation pattern, with radial ducts in teeth regions targeting high-loss areas, thereby preventing hot spots while maintaining manufacturing feasibility through modular duct integration
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 design effectively decreases thermal resistance and increases heat exchange area, preventing hot spots and extending the life expectancy of electrical machines by efficiently cooling the stator teeth and windings, even in large or high-power machines.
Implementation Method 1
the ducts are arranged internally in the laminated stator stack and interconnected to form a predominantly closed flow path, the outwards and inwards radial coolant ducts extent into the stator teeth, for cooling of the stator teeth
Implementation Method 2
circulating a liquid coolant in at least one axial coolant duct arranged in a yoke region of the laminated stator stack, circulating the liquid coolant in at least one outwards radial coolant duct, and returning the liquid coolant through at least one inwards radial coolant duct
Data Source
AI summary
The present invention relates to a laminated stator stack for an electric machine comprising, a plurality of stator teeth and stator slots, for receiving at least one electrical conductor, at least one axial coolant duct, at least one outwards radial coolant duct and at least one inwards radial coolant duct, wherein the ducts are arranged internally in the laminated stator stack and interconnected to form a predominantly closed flow path, the outwards and inwards radial coolant ducts extent into the stator teeth, for cooling of the stator teeth, and the laminated stator stack comprises a plurality of lamination sheets.