Slip Ring Recesses for Wind Turbine Cooling

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Solution Overview

Problem

Existing slip rings used in wind turbine generators face challenges in managing high thermal loads due to high current transmission, making it difficult to achieve a compact design while efficiently transmitting large amounts of electrical energy.

Innovation Solution

The design incorporates an air flow that travels axially through openings in the slip ring and is directed radially outward, passing through recesses and around contact areas to absorb thermal energy and cool the slip ring elements, particularly the side surfaces, allowing for a more compact and efficient cooling system without the need for forced ventilation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If the slip ring is made larger to reduce thermal stress, then the thermal management capability is improved, but the compactness and space efficiency deteriorate

Engineering Contradiction:
Improvethermal stressVSAvoidslip ring size
Core Design Contradiction:
TemperatureVSVolume of moving object

Solution Approach 1:

The slip ring is divided into multiple contact areas separated by insulating areas, with each contact area containing recesses that segment the airflow path. This segmentation allows efficient thermal management in a compact configuration by creating multiple localized cooling zones rather than requiring a single large cooling structure

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The recesses in the contact areas create three-dimensional cooling channels that extend into the slip ring structure. This vertical dimensionality allows cooling airflow to access internal surfaces and dissipate heat from multiple directions, achieving effective thermal management without increasing the overall footprint of the slip ring

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

2Device complexity

If conventional cooling designs are used, then the structural simplicity is maintained, but the cooling effectiveness deteriorates

Engineering Contradiction:
Improvecooling system structureVSAvoidcooling effectiveness
Core Design Contradiction:
Device complexityVSTemperature

Solution Approach 1:

The contact areas serve dual functions: electrical conduction and thermal management. The recesses in the contact areas simultaneously facilitate airflow distribution and direct cooling of the slip ring elements, eliminating the need for separate cooling components and maintaining structural simplicity while achieving effective cooling

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The slip ring structure itself provides the cooling functionality through its geometric design. The recesses in the contact areas automatically guide and distribute cooling airflow without requiring external control mechanisms or additional active cooling components, achieving self-service thermal management

Inventive Principle:
Principle #25Self-service

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 approach enables the slip ring to be made smaller, lighter, and more compact while effectively cooling the slip ring elements, thereby reducing thermal loads and improving the transmission of electrical energy, especially in the megawatt range.

Implementation Method 1

The airflow flows along the inside of the slip ring recess and absorbs heat energy

Methodology Applied
Scientific EffectHeat absorption: Absorption (physical)

Implementation Method 2

an airflow is conveyed axially through openings into the slip ring and then radially outwards through openings. The airflow flows along the inside of the slip ring recess and absorbs heat energy

Methodology Applied
Scientific EffectConvection: Convection

Data Source

PatentEP3788681B1Slip ring, slip ring unit, electric machine and wind turbine
Publication Date: 2023.01.04 FLENDER GMBH
  • EP3788681B1 patent drawingFigure 1
  • EP3788681B1 patent drawingFigure 2
  • EP3788681B1 patent drawingFigure 3

AI summary

The invention relates to a slip ring (1), a slip ring unit (17), and an electric machine comprising such a slip ring (1). The slip ring (1) is used to transmit electric energy from a stationary unit (13) to a contact region (5) via an electrically conductive slip ring element (11). The contact region (5) has at least one recess (7) in a tangential direction (t). The recess (7) or insulating layers (9) arranged between the contact regions (5) have at least one protrusion (8), wherein the protrusions (8) produce an airflow (15) for cooling the contact region (5) and/or the slip ring element (11), in particular during a rotational movement of the slip ring (1). In order to improve the airflow (15), openings (10) are introduced into annular surfaces (12) which are formed by an increased radius of the contact region (5) compared to the adjacently arranged insulating regions (9). The openings (10) are preferably used to transfer the airflow (15) into the respective recess (7). By virtue of the features of the invention, large quantities of electric energy can be transmitted with a compact design of the slip ring (1). The slip ring (1) is therefore suitable for use in a wind turbine in particular.