Stator Winding Configuration for Rotating Electric Machine
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Solution Overview
Problem
Existing stator designs for rotating electric machines in vehicles face issues with circulating currents between parallel windings and increased axial length of coil end portions due to overlapping conductor segments, which affect efficiency and space utilization.
Innovation Solution
A stator design with a stator core having circumferentially arranged slots and phase windings formed by U-shaped conductor segments, where each phase winding is a parallel connection of 4×n parallel windings, with bent open end portions electrically connected in a star pattern to prevent circulating currents and maintain balanced winding configurations, using a combination of five and seven slot pitch switchings to alternate slot groups and evenly distribute slot-received portions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If outer and inner conductor segments are arranged at six slot intervals with overlapping configuration, then the phase winding can be formed, but the axial length of the coil end portion increases due to triple or quadruple overlap
Solution Approach 1:
The patent divides the conductor segments into distinct groups (first conductor segments for third and fourth layers, second conductor segments for second and fifth layers, third conductor segments for first and sixth layers) and assigns them to different slot intervals (five, six, and seven slot intervals respectively). This segmentation prevents overlapping by ensuring each group occupies a unique axial position, thereby reducing the axial length of the coil end portion while maintaining proper winding formation.
Solution Approach 2:
The patent introduces a new dimension of control by varying the slot interval pitch (five, six, and seven slots) for different conductor segment groups. Instead of using a uniform six-slot interval that causes overlap, the invention distributes conductor segments across multiple interval dimensions, effectively eliminating axial overlap while preserving the electrical connectivity requirements of the phase winding.
2Reliability
If five slot pitch and seven slot pitch based switching are used to alternate slot groups, then circulating current can be prevented, but the configuration complexity increases
Solution Approach 1:
The patent applies different slot interval characteristics to different conductor segment groups locally. First conductor segments use five slot intervals, second conductor segments use six slot intervals, and third conductor segments use seven slot intervals. This localized differentiation prevents circulating currents by ensuring that parallel windings experience different magnetic paths, while the overall configuration remains systematic and manageable through clear group assignment rules.
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 completely prevents circulating currents between parallel windings while maintaining a balanced axial length of the coil end portions, enhancing efficiency and preventing axial length increase, thus optimizing the stator's performance and space usage.
Implementation Method 1
ends of given bent portions of the conductor segments are welded to each other such that the phase windings are electrically star connected to each other
Implementation Method 2
a rotating electric machine including a rotor, a stator core, and a stator having a stator winding formed of a plurality of phase windings
Data Source
AI summary
A stator core with a plurality of slots circumferentially arranged therearound has a stator winding including three (UVW) phase windings, each phase winding having 4n parallel windings. The stator winding is formed of U-shaped conductor segments inserted in the slots from one axial end, a pair of open end portions of each conductor segment extending axially from of the stator core and being bent toward circumferentially opposite directions, the bent portions being star connected together. The plurality of slots have, for each phase winding, pairs of circumferentially adjacent slots, each slot having an even number of slot-received portions of the phase winding radially aligned in a column, and for each circumferential slot pairs, the slot-received portion in an m-th layer of each slot of the pair is electrically connected to the portion inserted in an (m+1)-th layer of a slot of a circumferentially adjacent slot.