Outer-Diameter Bus Bar Stator for Shorter Axial Packaging
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Solution Overview
Problem
Existing electric machine stators face challenges in packaging due to the tall bus bars required for connecting leads, especially with increased number of slots per pole per phase, parallel wires, and series connections, which worsens space constraints in vehicle engine compartments.
Innovation Solution
A stator design with a bus bar assembly that includes inner and outer bus bars positioned radially and axially to reduce the overall length of the stator, allowing for easier manufacturing and improved space utilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional bus bar configuration is used to connect leads, then electrical connections are established, but the axial length of the stator increases
Solution Approach 1:
The bus bar configuration transitions from a primarily axial arrangement to a radial arrangement. The bus bars extend radially outward from the stator core rather than axially, allowing connections to be made in the radial dimension while reducing axial length requirements.
Solution Approach 2:
The bus bars are positioned within the space between the stator core and the outer housing, utilizing the radial space that would otherwise be unused. This nesting approach allows the bus bars to be contained within the existing radial envelope of the motor without increasing axial length.
2Adaptability or versatility
If increased number of slots per pole per phase is used to improve winding complexity, then electrical performance is enhanced, but bus bar height increases
Solution Approach 1:
The bus bar connection strategy shifts from vertical stacking (axial direction) to radial arrangement. By connecting leads that emerge radially from the stator slots, the bus bars can be positioned in the radial plane rather than stacked axially, reducing height while accommodating more connections.
Solution Approach 2:
The bus bar system is divided into multiple segments or sections that can be arranged radially around the stator core. Each segment handles specific phase connections, allowing multiple connections to be distributed in the radial dimension rather than stacked vertically.
3Adaptability or versatility
If series connections between winding paths are increased, then electrical performance is improved, but stator footprint increases
Solution Approach 1:
Series connections are arranged in the radial and circumferential dimensions rather than extending axially. The bus bars are positioned to make connections in the radial plane, allowing multiple series connections to be packed into the radial-circumferential space without increasing axial footprint.
Solution Approach 2:
The radial bus bar configuration serves multiple functions simultaneously: it provides series connections between winding paths, establishes phase connections, and maintains compact dimensions. This multi-functional design accommodates increased connection complexity without proportionally increasing footprint.
Data Source
AI summary
A stator for an electric machine comprises a cylindrical core defining an inner cylindrical surface and an outer cylindrical surface with a plurality of slots formed between the inner cylindrical surface and the outer cylindrical surface. Windings are positioned on the cylindrical core. The leads of the windings include a plurality of inner leads associated with conductors in an inner layer of the slots and a plurality of outer leads associated with conductors in an outer layer of the slots. A bus bar assembly includes a plurality of inner bus bars and a plurality of outer bus bars, the plurality of inner bus bars connected to the plurality of inner leads, and the plurality of outer bus bars connected to the plurality of outer leads. The plurality of outer bus bars are positioned radially outward from the end turns of the windings and radially inward from the outer cylindrical surface.