Unequal Stator Slot Layout for Low-Harmonic Asynchronous Motors

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Solution Overview

Problem

Three-phase asynchronous motors with low harmonic and unequal turns winding face challenges in optimizing slot fullness and embedding quality, leading to increased stray losses, temperature rise, and noise, which affect efficiency and performance.

Innovation Solution

A stator lamination design with unequal slots, featuring a ring-shaped substrate with radially arranged stator slot groups, including large and small slots, optimized in shape and arrangement to achieve consistent slot fullness and improved embedding quality, reducing stray losses and temperature rise.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the same slot shape is used in the stator lamination, then the manufacturing process is simple, but the slot fullness becomes inconsistent when the number of turns of each coil is different, leading to poor embedding quality

Engineering Contradiction:
Improveslot fullness consistencyVSAvoidslot shape design
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent applies local quality by designing different slot shapes for different coil types. Specifically, coils with fewer turns use slots with larger opening widths, while coils with more turns use slots with smaller opening widths. This localized adaptation of slot geometry to the specific winding requirements of each coil position ensures consistent slot fullness across all coils, directly resolving the contradiction between manufacturing precision and device complexity.

Inventive Principle:
Principle #3Local quality

2Manufacturing precision

If unequal slots are designed to accommodate different number of turns, then the embedding quality improves, but the manufacturing complexity increases

Engineering Contradiction:
Improveembedding qualityVSAvoidslot fabrication
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent applies parameter changes by systematically varying the opening width parameter of the slot geometry based on the coil turn count. The opening width is adjusted within a specific range (0.5-2.0mm) to optimize slot fullness for different winding configurations. This controlled parameter variation allows the patent to improve embedding quality while keeping the manufacturing process manageable through standardized geometric modifications rather than completely different slot designs.

Inventive Principle:
Principle #35Parameter changes

3Adaptability or versatility

If the slot opening width is increased, then coils with fewer turns can be accommodated, but the slot fullness decreases for coils with more turns

Engineering Contradiction:
Improvecoil accommodationVSAvoidslot fullness
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The patent resolves this contradiction by applying local quality through position-specific slot design. Each slot opening width is locally optimized according to the coil's turn count and position in the stator. Coils with fewer turns are placed in slots with larger opening widths to ensure proper accommodation, while coils with more turns are placed in slots with smaller opening widths to maintain high slot fullness. This localized adaptation allows the system to achieve both adaptability and manufacturing precision simultaneously.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP3998694B1Stator lamination having slots of unequal size for use in three-phase asynchronous motor having low harmonic wave windings having unequal number of turns
Publication Date: 2023.12.20 SHANXI ELECTRIC MOTOR MANUFACTURING CO LTD
  • EP3998694B1 patent drawingFigure 1~3
  • EP3998694B1 patent drawingFigure 4~6
  • EP3998694B1 patent drawingFigure 7~9

AI summary

The present invention discloses a stator lamination with unequal slots for use in three-phase asynchronous motor having low harmonic and unequal turns winding, including a ring-shaped substrate, wherein stator slot groups are radially and uniformly arranged on the inner ring surface of the substrate along the circumference direction of the substrate. The number of stator slots per pole and phase in each stator slot group is three to nine, including at least one large stator slot and at least two small stator slots, wherein the at least one large stator slot is arranged in the middle of the stator slot group, and the two sides of the large stator slot are respectively symmetrically arranged with one or more small stator slots. Or, the number of stator slots per pole and phase in each stator slot group is five to nine, including at least one large stator slot, at least two middle stator slots and at least two small stator slots, wherein the at least one large stator slot is arranged in the middle of the stator slot group, the two sides of the large stator slot are respectively symmetrically arranged with one or more small stator slots, and between the large stator slot and the small stator slot are respectively symmetrically arranged with one or more middle stator slots.