Variable-Section Stator Windings for Direct Cooling in Axial Flux Motors
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Solution Overview
Problem
Conventional stator windings in electric motors, particularly in axial flux motors, face inefficiencies due to constant winding width and resistance, which limits power generation and heat dissipation, making them less effective in high-torque applications like electric vehicles.
Innovation Solution
The use of three-dimensionally printed or rolled stator windings with variable cross-sections and integrated coolant channels, where the width increases radially outward, reducing winding resistance and enhancing heat transfer through coolant circulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional stator windings with constant width are used, then the structure is simple to manufacture, but the filling rate at outer diameter is low and winding resistance is high
Solution Approach 1:
The stator winding cross-section is designed with variable width along the radial direction, where the width at the outer diameter is greater than the width at the inner diameter. This local variation in geometry optimizes the filling rate at different radial positions, increasing the amount of conductive material at the outer diameter where the magnetic flux density is higher, thereby improving overall power generation efficiency without complicating the manufacturing process beyond conventional capabilities
2Ease of manufacture
If conventional stator windings with constant width are used, then the manufacturing process is simple, but heat dissipation is insufficient
Solution Approach 1:
The variable cross-section design increases the winding width at the outer diameter, which naturally increases the surface area available for heat dissipation. Additionally, the increased conductive material volume at the outer diameter provides better thermal pathways for heat generated in the windings to conduct outward to cooling structures, improving heat dissipation efficiency while maintaining manufacturing simplicity
3Productivity
If stator windings with variable cross-section are used, then the filling rate at outer diameter increases, but the manufacturing complexity increases
Solution Approach 1:
The winding cross-sectional width parameter is varied continuously or in steps along the radial direction, transitioning from a constant width design to a variable width design. This parameter change optimizes the filling rate at the outer diameter by providing more conductive material where the magnetic flux density is highest, thereby improving power generation efficiency. The complexity increase is managed by using standard manufacturing techniques that can accommodate variable cross-sections
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 increases the filling rate at the outer diameter, decreases winding resistance, improves motor efficiency, and effectively manages heat dissipation, leading to enhanced performance in high-torque applications such as electric vehicles.
Implementation Method 1
The N stator windings include coolant channels through the N stator windings
Implementation Method 2
a pump configured to pump a coolant through the coolant channels
Data Source
AI summary
An axial flux motor includes: a stator having a first side and a second side opposite the first side, the stator including: N stator core components on the first side, where N is an integer greater than two; N stator windings that are disposed around the N stator core components, respectively, where each of the N stator windings includes, from a point of view facing the first side: a first width at a first location; and a second width that is greater than the first width at a second location that is radially outward from the first location relative to an axis; slot openings disposed between adjacent ones of the stator windings; and a rotor including a third side and M permanent magnets on the third side, where the first side is parallel to the third side, and where M is an integer greater than or equal to two.