Stator Assembly With Axial Open-Closed Grooves for Eddy Loss Control
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Solution Overview
Problem
Existing stator assemblies in electric machines suffer from high eddy current losses and instability due to open grooves, particularly in high-performance applications like electric vehicles, which also affect the stability and cooling efficiency.
Innovation Solution
A stator assembly design featuring open grooves at axial ends and closed grooves in the central region, combined with a collimator made of magnetically non-conductive plastic, enhances stability and reduces eddy currents while allowing direct cooling through the grooves.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If open grooves are used in the stator assembly, then cooling efficiency is improved, but eddy current losses increase and stability deteriorates
Solution Approach 1:
The patent applies different groove configurations to different axial regions of the stator assembly. The first and second axial regions (at the ends) have open grooves for cooling, while the third axial region (central region) has closed grooves to reduce eddy currents. This local differentiation resolves the contradiction by optimizing each region for its specific function.
Solution Approach 2:
The stator assembly is segmented into multiple axial regions with different groove characteristics. The grooves are divided into at least three groups along the axial direction, with different open/closed configurations. This segmentation allows simultaneous optimization of cooling (open grooves) and eddy current reduction (closed grooves) in different segments.
2Temperature
If open grooves are used in the stator assembly, then cooling efficiency is improved, but stability deteriorates
Solution Approach 1:
Different axial regions are assigned different groove configurations tailored to their functional requirements. End regions use open grooves for cooling access, while the central region uses closed grooves for structural stability. This local quality approach resolves the stability-cooling contradiction.
Solution Approach 2:
The stator assembly is divided into multiple axial regions with differentiated groove structures. This segmentation allows the cooling function (open grooves) and stability function (closed grooves) to coexist in different parts of the same component.
3Loss of energy
If closed grooves are used in the central region, then eddy current losses are reduced and stability is improved, but cooling efficiency may be compromised
Solution Approach 1:
The central region is specifically designed with closed grooves to minimize eddy currents, while end regions maintain open grooves for cooling. This local quality differentiation ensures that the trade-off is acceptable overall because cooling is prioritized where it matters most (ends) while stability is prioritized in the center.
Solution Approach 2:
The groove structure is segmented axially with closed grooves in the central region and open grooves in end regions. This segmentation allows each region to be optimized for its primary function without completely compromising the other function in different parts of the assembly.
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 configuration significantly reduces eddy current losses, improves stability, and enables effective cooling, making it suitable for high-performance electric machines.
Implementation Method 1
significantly reduces eddy current losses
Implementation Method 2
collimator made of magnetically non-conductive plastic
Data Source
AI summary
A stator assembly for an electric machine, including a sheet metal package, a winding assembly, and a collimator. The sheet metal package includes sheets and extends between a first and second axial end. The sheets include grooves forming groove pockets in the sheet metal package. The winding assembly extends through the groove pockets, the groove pockets at least partially including a first plurality of grooves configured as open grooves in a first axial region provided at the first axial end, a second plurality of grooves configured as open grooves in a second axial region provided at the second axial end, and a third plurality of grooves in at least one third axial region, the at least one third axial region lying between the first axial region and the second axial region. The third plurality of grooves are configured as closed grooves.