Generator Lamination Torque Transfer

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Solution Overview

Problem

Direct drive wind turbines face challenges with heavy and expensive generator housings due to high torque requirements, thermal barriers, and corrosion protection, which hinder efficient heat transfer and increase costs.

Innovation Solution

The laminations take over the structural function of the housing, transferring torque axially without a separate housing, using coatings for corrosion protection, and incorporating permanent magnets and enlarged lamination surfaces for improved cooling, eliminating the need for active cooling systems.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a housing is used to transfer torque from laminations to mounting points, then torque transfer capability is improved, but weight and cost increase

Engineering Contradiction:
Improvetorque transfer capabilityVSAvoidhousing weight
Core Design Contradiction:
StrengthVSWeight of stationary object

Solution Approach 1:

The housing and lamination package are merged into a single integrated structure where the laminations directly form the torque-transferring component. The lamination package is secured between front and rear plates with bolts that transfer torque axially from the laminations to the mounting points, eliminating the need for a separate housing structure.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The housing is extracted from the design entirely, removing this non-essential component while retaining its torque transfer function through the integrated lamination package and mounting structure.

Inventive Principle:
Principle #2Taking out (Extraction)

2Reliability

If a housing is used to protect laminations from corrosion, then corrosion protection is improved, but weight and cost increase

Engineering Contradiction:
Improvecorrosion protectionVSAvoidhousing weight
Core Design Contradiction:
ReliabilityVSWeight of stationary object

Solution Approach 1:

Instead of using a housing for overall protection, local corrosion protection is applied directly to the lamination surfaces through coatings. The front and rear plates provide localized protection at critical interfaces, while the laminations themselves are protected where needed.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The housing is removed from the design, and its protective function is replaced by direct coating applications on the laminations and selective protection at mounting interfaces.

Inventive Principle:
Principle #2Taking out (Extraction)

3Strength

If a housing is used to transfer torque, then structural strength is improved, but heat transfer capability deteriorates

Engineering Contradiction:
Improvestructural strengthVSAvoidheat transfer efficiency
Core Design Contradiction:
StrengthVSTemperature

Solution Approach 1:

The housing is extracted from the design, removing the thermal barrier it created. The laminations are now directly exposed to ambient air, allowing efficient convective and radiative heat transfer from the rotating lamination package without the insulating effect of a housing enclosure.

Inventive Principle:
Principle #2Taking out (Extraction)

4Weight of stationary object

If laminations are made thin to reduce weight, then material weight is reduced, but torque transfer capability deteriorates

Engineering Contradiction:
Improvelamination weightVSAvoidtorque transfer capability
Core Design Contradiction:
Weight of stationary objectVSStrength

Solution Approach 1:

The lamination package consists of many thin individual laminations stacked together. While each lamination is thin and lightweight, the collective stack of numerous laminations provides sufficient torque transfer capability through the cumulative effect of all laminations working together, secured by axial bolts.

Inventive Principle:
Principle #1Segmentation

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 reduces the weight and cost of the generator while enhancing torque transfer and heat dissipation, increasing turbine efficiency and availability, particularly in larger turbines where active cooling is typically required.

Implementation Method 1

the laminations transfer the torque to the mounting points of the generator

Methodology Applied
Scientific EffectTorque transfer: Torque

Implementation Method 2

incorporating permanent magnets and enlarged lamination surfaces for improved cooling

Methodology Applied
Scientific EffectHeat dissipation: Thermal Radiation

Implementation Method 3

The outside of the lamination package is directly exposed to the ambient air

Methodology Applied
Scientific EffectConvection: Convection

Implementation Method 4

using coatings for corrosion protection

Methodology Applied
Scientific EffectCorrosion protection: Coatings

Implementation Method 5

incorporating permanent magnets

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP2232066B1Generator for direct drive wind turbine
Publication Date: 2017.12.20 LAGERWEY WIND BV
  • EP2232066B1 patent drawingFigure 1
  • EP2232066B1 patent drawingFigure 2
  • EP2232066B1 patent drawingFigure 3~4

AI summary

Direct driven wind turbine comprising a tower, a nacelle, a rotor blade, a radial flux generator with a stator and a rotor, wherein the lamination package of the generator is essential for the transfer of the torque in axial direction. By introducing this additional function to the lamination package, the generator can be provided without additional torque transferring housing. According to an embodiment of the invention the lamination package obtains this additional function by pressing together the laminations between the front plate and end plate by tensile bolts. This gives sufficient strength to transport the torque in axial direction through the laminations to the mounting points of the generator. Further advantage is obtained by supplying the laminations of cooling fins. Due to these measures the cooling of the generator improves and active cooling may become superfluous or the power can be increased. The housing of the laminations is an expensive, heavy and labour intensive part which is no longer required due to the invention.