Double-Layer Stator Coil Layout for Lower Spatial Harmonics
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Solution Overview
Problem
The existing stator designs for rotary electric machines face complications due to the alternation of double-wound coil portions and single-wound coil portions, leading to an increased number of coil types and a complex winding method.
Innovation Solution
A stator design utilizing a multi-phase stator coil wound by double-layer winding, where a plurality of double-wound coils are wound concentrically with different circumferential lengths around the entire circumference of the stator core, each composed of a larger and a smaller circumferential length coil portion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If double-wound coil portions and single-wound coil portions are alternately arranged in the circumferential direction, then spatial harmonics can be reduced, but the number of coil types increases and the winding method becomes complicated
Solution Approach 1:
The patent applies local quality by creating different coil portions (first coil portion with larger circumferential length, second coil portion with smaller circumferential length) within the same double-wound coil structure. Each coil portion is inserted into different slots (first slots and second slots respectively) with different circumferential positions, allowing local variation in coil distribution to reduce spatial harmonics while maintaining overall structural simplicity through a unified double-wound coil design.
2Object-generated harmful factors
If multiple types of coils are used to reduce spatial harmonics, then harmonic reduction is achieved, but manufacturing complexity increases
Solution Approach 1:
The patent merges the functionality of multiple coil types into a single double-wound coil structure. The first coil portion and second coil portion are both part of the same double-wound coil, which is formed by winding a conductor around a mandrel and then removing the mandrel. This unified structure simplifies manufacturing compared to using separate single-wound coils, while still achieving harmonic reduction through the different circumferential lengths of the two coil portions.
3Object-generated harmful factors
If different circumferential lengths of coils are used, then spatial harmonics are reduced, but coil end size increases
Solution Approach 1:
The patent addresses the coil end volume issue by transitioning from a planar arrangement to a three-dimensional double-layer winding structure. The first coil portion and second coil portion are arranged in different radial layers, with the first coil portion having larger circumferential length and the second coil portion having smaller circumferential length. This vertical stacking in the radial direction allows different circumferential lengths without proportionally increasing the overall coil end volume, as the portions occupy different spatial zones in the radial dimension.
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 reduces spatial harmonics while maintaining the simplicity of using only one type of double-wound coil, thereby improving the winding method and reducing the size of coil ends.
Implementation Method 1
a multi-phase stator coil wound around the stator core by double-layer winding
Data Source
AI summary
A stator for a rotary electric machine, including a stator core having a plurality of slots, and a multi-phase stator coil wound around the stator core by double-layer winding. The multi-phase stator coil is formed by winding a plurality of double-wound coils around an entire circumference of the stator core for each phase, each of the double-wound coils being wound concentrically with different circumferential lengths. Each of the double-wound coils is formed of a coil portion having a larger circumferential length and a coil portion having a smaller circumferential length. In one of the double-wound coils, a total number of coils inserted into the plurality of slots for the coil portion having the larger circumferential length and a total number of coils inserted into the plurality of slots for the coil portion having the smaller circumferential length are equal to each other.