Concentrated Stator Windings With Split Slots for Easier Coil Insertion
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Solution Overview
Problem
Conventional concentrated winding designs in electric generators, such as those in wind turbines, face challenges with coil insertion due to narrow coil widths and long coil overhang lengths, which can damage insulation and reduce fill factor, especially in designs with rectangular slots and tapered teeth, or compromise performance by using non-active insulation material in V-shaped slots.
Innovation Solution
A stator geometry with radially extending slots having both a bottom and top portion, where coils in the bottom portion of one slot are connected to coils in the top portion of an adjacent slot, reducing coil overhang length and allowing easier insertion without damaging insulation, while maintaining or improving performance by optimizing the fill factor of conducting material.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If rectangular slots with tapered teeth are used, then the slot structure is simple, but the coil overhang length increases making insertion difficult and risking insulation damage
Solution Approach 1:
The slot is divided into two distinct portions: a first portion with a first cross-sectional shape (wider at the open end) and a second portion with a second cross-sectional shape (narrower). This segmentation allows the slot to accommodate coils with reduced overhang while maintaining structural integrity, solving the contradiction between simple structure and ease of insertion.
Solution Approach 2:
The invention transitions from a uniform slot cross-section to a variable cross-section along the radial direction. By changing the cross-sectional dimensions from the first portion to the second portion, the slot creates additional spatial dimension for coil accommodation, reducing the required coil overhang length while keeping the overall structure simple.
2Ease of operation
If V-shaped slots with insulation material are used, then coil insertion is easier, but the fill factor decreases due to non-active insulation material
Solution Approach 1:
The slot cross-section is segmented into different regions along the radial direction, with the first portion having larger dimensions for easier coil insertion and the second portion optimized for filling. This eliminates the need for insulation material in the middle of the slot while maintaining both ease of insertion and high fill factor.
Solution Approach 2:
The slot dimensions are changed as a function of radial position, with the first portion having different cross-sectional parameters than the second portion. This parameter variation allows the slot to provide insertion-friendly geometry at the open end while maximizing the active material volume in the deeper portion, achieving both ease of operation and high fill factor without insulation material.
3Ease of operation
If long coil overhang length is used, then coil insertion is possible in rectangular slots, but the risk of insulation damage increases
Solution Approach 1:
The slot is segmented into a first portion with larger cross-sectional dimensions that accommodates the coil insertion process, and a second portion with smaller dimensions that secures the coil. This segmentation reduces the required coil overhang length while ensuring proper insertion, thereby minimizing insulation damage risk while maintaining insertion feasibility.
Data Source
AI summary
Provided is an electric generator including a stator including:a stator yokea plurality of teeth,a plurality of slots extending radially from the stator yoke to respective radial slot ends, the plurality of slots being circumferentially interposed between the teeth of the stator, each slot including a bottom portion adjacent to the stator yoke and a top portion adjacent to the respective radial slot end. The stator further includes a plurality of coils housed in the plurality of slots, each slot housing at least one coil in the bottom portion and at least another coil in the top portion, each coil housed in the bottom portion of a first slot of the plurality of slots being connected to another respective coil housed in the top portion of a second slot of the plurality of slots.