Generator Air-Guiding Layout for Direct-Drive Winding Head Cooling

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Solution Overview

Problem

The cooling efficiency of stator windings in direct drive permanent magnet generators is limited due to the complex geometry of the winding heads, resulting in increased operating temperatures and reduced output power.

Innovation Solution

A generator design with an air guiding arrangement that separates the cooling volume into radial inner and outer sections, using air deflection sheets to create a nozzle effect and increase the contact surface between cooling air and winding heads, enhancing heat transfer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If forced air-cooling system is applied with cool air entering from NDE and DE sides, then cooling coverage is provided, but contact surface with winding heads is small and heat dissipation is insufficient

Engineering Contradiction:
Improvewinding head temperatureVSAvoidcooling system structure
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The cooling volume is segmented into a radial inner section and a radial outer section using an air guiding arrangement. This segmentation directs cooling air specifically to the winding heads, increasing the contact surface area and heat dissipation efficiency without significantly increasing overall system complexity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

An air guiding arrangement acts as an intermediary component between the cooling air source and the winding heads. This intermediary structure optimizes the flow path and contact between cooling air and winding heads, improving heat transfer efficiency while maintaining a relatively simple cooling system structure.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Temperature

If large chamber volume is provided on NDE and DE side, then cooling air flow is accommodated, but contact surface with winding heads is reduced and cooling performance decreases

Engineering Contradiction:
Improvewinding head temperatureVSAvoidcooling chamber volume
Core Design Contradiction:
TemperatureVSVolume of stationary object

Solution Approach 1:

Instead of uniformly distributing cooling air throughout the large chamber volume, the air guiding arrangement creates localized high-velocity flow regions directly at the winding heads. This local quality enhancement ensures effective cooling at critical locations while accepting larger overall chamber volume.

Inventive Principle:
Principle #3Local quality

3Power

If complex geometry of stator winding heads is maintained, then electrical performance is optimized, but cooling efficiency is reduced due to limited air contact

Engineering Contradiction:
Improvegenerator output powerVSAvoidwinding head temperature
Core Design Contradiction:
PowerVSTemperature

Solution Approach 1:

The air guiding arrangement introduces a radial dimension to the cooling air flow, directing air from the radial inner section through the air inlet opening into the radial outer section where winding heads are located. This dimensional approach increases contact surface area without altering the complex three-dimensional geometry of the winding heads themselves, thereby maintaining electrical performance while improving cooling efficiency.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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

Improved cooling efficiency leads to reduced winding temperatures, increased generator power, and extended component lifespan, with higher reliability and efficiency.

Implementation Method 1

The air guiding arrangement forms an air inlet opening, such that cooling air is flowable from the radial inner section against the air guiding arrangement and through the air inlet opening into the radial outer section

Methodology Applied
Scientific EffectNozzle effect: De Laval Nozzle

Implementation Method 2

cooling air enters the generator from the non-drive end (NDE) and drive end (DE) sides, and after passing over the stator winding heads, it enters an axial gap between the rotor and the stator and is distributed between a number of radial air ducts in the stator body to remove heat

Methodology Applied
Scientific EffectConvection: Convection

Data Source

PatentEP4597799A1Cooling technique to reduce generator hot spot in direct drive permanent magnet wind turbines
Publication Date: 2025.08.06 SIEMENS GAMESA RENEWABLE ENERGY AS
  • EP4597799A1 patent drawingFigure 1~2A
  • EP4597799A1 patent drawingFigure 2B
  • EP4597799A1 patent drawingFigure 3~4

AI summary

The present invention describes a generator (100) for a wind turbine, comprising a rotor device (101) rotatable around a rotary axis (107), a stator device (102) comprising a winding arrangement (103),wherein between an axial end of the stator device (102) and the rotor device (101) a cooling volume is formed, and an air guiding arrangement (120) arranged within the cooling volume for separating the cooling volume into a radial inner section (112) and a radial outer section (113). The air guiding arrangement (120) forms an air inlet opening (104), such that cooling air (111) is flowable from the radial inner section (112) against the air guiding arrangement (120) and through the air inlet opening (104) into the radial outer section (113), wherein the winding arrangement (103) extends from the axial end of the stator into the radial outer section (113).