Wind Turbine Generator Stator Wedge Layout for Coil Heat Dissipation

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Solution Overview

Problem

Wind turbine generator stators with preformed coils experience high temperatures due to increased current density, leading to potential insulation damage and ground faults, especially in large turbines. Existing cooling measures are complex and inefficient in densely packed stator slots.

Innovation Solution

A wedge is pressed between the outer sides of the legs of preformed coils in the stator slots, ensuring a force is exerted on the legs to create a more ideal contact with the stator teeth, enhancing heat dissipation. This solution includes using a plastic wedge, such as glass-fiber-reinforced plastic, and inserting woven or nonwoven fabrics between the wedge and the legs to increase frictional resistance and stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If preformed coils are used to increase fill factor, then power density is improved, but temperature increases due to higher current density

Engineering Contradiction:
Improvepower densityVSAvoidcoil temperature
Core Design Contradiction:
PowerVSTemperature

Solution Approach 1:

The patent applies local quality by creating different contact conditions at different locations of the preformed coil. The legs are pressed against the stator teeth with increased contact pressure through the wedge mechanism, while other parts of the coil maintain their original structure. This localized improvement in contact quality at the critical heat dissipation points (legs-stator tooth interfaces) enables better thermal management without compromising the overall high fill factor design.

Inventive Principle:
Principle #3Local quality

2Temperature

If active or passive ventilation is used to cool coils, then temperature is reduced, but device complexity increases

Engineering Contradiction:
Improvecoil temperatureVSAvoidcooling system complexity
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The patent implements self-service cooling by utilizing the existing structural components (stator teeth and preformed coil legs) to perform the cooling function. The wedge mechanism creates self-contact pressure that enhances heat dissipation through improved thermal contact, eliminating the need for separate active or passive ventilation systems. The structure serves its own cooling needs through the press-fit arrangement and inherent thermal pathways.

Inventive Principle:
Principle #25Self-service

3Temperature

If insulation is designed to be heat-resistant, then temperature resistance is improved, but manufacturing complexity increases

Engineering Contradiction:
Improvetemperature resistanceVSAvoidinsulation manufacturing
Core Design Contradiction:
TemperatureVSEase of manufacture

Solution Approach 1:

The patent converts the harmful effect of high temperature into a beneficial design feature by deliberately creating controlled contact pressure points. The wedge mechanism transforms the thermal stress problem into a mechanical solution where the press-fit arrangement and friction forces are used to enhance heat dissipation pathways. This approach uses the thermal challenge itself to drive the design of improved thermal contact rather than merely resisting heat through more complex insulation.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

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

The improved contact between the preformed coil legs and the stator teeth significantly reduces heat generation in the preformed coils, enhancing the reliability of the wind turbine generator stator by minimizing the risk of insulation damage and ground faults.

Implementation Method 1

inserting woven or nonwoven fabrics between the wedge and the legs to increase frictional resistance and stability

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

the current flowing in the preformed coils, which is converted into heat by the resistance of the preformed coils, creates temperatures in the wind turbine generator stator

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Data Source

PatentEP4568071A1Wind turbine generator stator for a wind turbine with form coils and method for producing a wind turbine generator stator
Publication Date: 2025.06.11 WOBBEN PROPERTIES GMBH
  • EP4568071A1 patent drawingFigure 1
  • EP4568071A1 patent drawingFigure 2~3
  • EP4568071A1 patent drawingFigure 4~5

AI summary

The invention relates to a wind turbine generator stator (10) with a plurality of stator teeth (14) and stator slots (16), in particular arranged in alternating circumferential directions, and a plurality of preformed coils (40) inserted into the stator slots (16). Each preformed coil (40) comprises a partial winding (48) consisting of a plurality of turns (46a, 46b, 46c). Before being inserted into the stator slot (16), the turns (46a, 46b, 46c) are wound from at least one electrical conductor (45) in such a way that the partial winding (48) is formed from winding heads (42) arranged at two opposite ends of the partial winding (48) and two essentially parallel legs (44). Two legs (44) of different preformed coils (40) are inserted into at least one stator slot (16) in such a way that outer sides (54) of the legs (44) face each other and inner sides (52) of the legs (44) each face a different one of the two stator teeth (14) delimiting the stator slot (16).A wedge (60) is pressed between the outer sides (54) of the legs (44), so that the wedge (60) exerts a force on the outer side (54) of each leg (44). The invention further relates to a method for producing a wind turbine generator stator (10), a wind turbine generator with a wind turbine generator stator (10), and a wind turbine (100) with a wind turbine generator or a wind turbine generator stator (10).