Wind Turbine Ring Generator Cooling via Stator Bell

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Solution Overview

Problem

Ring generators in wind power plants face inefficiencies in cooling due to their slow rotational speed, which limits self-cooling capabilities and introduces risks of corrosion with water cooling methods.

Innovation Solution

The design incorporates a stator bell connected to the stator ring to create a pressure chamber for active air cooling, with both active and passive cooling channels, and uses a segmented stator ring made of aluminum for enhanced thermal conductivity and corrosion resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If self-cooling by a propeller mechanically fixed to the rotor is used, then cooling is achieved, but it is impossible or not very efficient due to slow rotational speed

Engineering Contradiction:
Improvecooling efficiencyVSAvoidrotational speed
Core Design Contradiction:
TemperatureVSSpeed

Solution Approach 1:

The patent applies self-service by utilizing the kinetic energy of the wind itself to drive the propeller for cooling purposes. The propeller is mechanically coupled to the rotor, so that the rotational motion of the rotor directly drives the propeller to intake and circulate cooling air through the generator components, eliminating the need for separate power sources or external cooling systems.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent employs pneumatic principles by using air flow generated by the propeller to cool the generator. Cooling air is drawn in through inlet openings, forced through cooling channels in the stator and rotor, and expelled through outlet openings. This pneumatic cooling system replaces inefficient thermal conduction methods and provides active heat dissipation.

Inventive Principle:
Principle #29Pneumatics and hydraulics

2Temperature

If water cooling is used to increase cooling efficiency, then cooling is improved, but corrosion risk increases due to contact with metallic components

Engineering Contradiction:
Improvecooling efficiencyVSAvoidcorrosion risk
Core Design Contradiction:
TemperatureVSReliability

Solution Approach 1:

The patent uses air as an intermediary cooling medium instead of direct water contact with metallic components. The cooling air flows through sealed cooling channels, providing thermal convection cooling without causing corrosion. This intermediary approach maintains effective heat dissipation while protecting the metallic stator and rotor from corrosive damage.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent creates an inert atmospheric cooling environment by using dry air instead of water. The cooling air, which is chemically inert toward the metallic components, circulates through the generator interior, providing cooling without introducing corrosive elements. This inert environment preserves the integrity of metallic parts over time.

Inventive Principle:
Principle #39Inert atmosphere (Inert environment)

3Temperature

If an external rotor with support arms designed as blades is used to convey cooling air, then cooling is achieved, but the structure becomes extremely complicated and expensive

Engineering Contradiction:
Improvecooling efficiencyVSAvoidstructural complexity
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The patent applies multi-functionality by integrating the rotor blades with the cooling air conveyance function. The rotor blades serve dual purposes: generating mechanical energy from wind and simultaneously driving the propeller for cooling. This eliminates the need for separate support arms designed as blades, simplifying the overall structure while maintaining effective cooling.

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

Solution Approach 2:

The patent merges the energy generation function and cooling function into a unified system. The rotor and propeller are mechanically coupled so that the same rotational motion performs both functions. This consolidation eliminates redundant structural elements and reduces system complexity compared to separate cooling mechanisms.

Inventive Principle:
Principle #5Merging (Combining)

4Temperature

If a fan in the nacelle casing is used to press air through the air gap, then cooling is achieved, but additional mechanical complexity and energy consumption are introduced

Engineering Contradiction:
Improvecooling efficiencyVSAvoidenergy consumption
Core Design Contradiction:
TemperatureVSUse of energy by moving object

Solution Approach 1:

The patent applies self-service by using the wind's kinetic energy to drive the cooling system. The rotor, driven by wind, mechanically couples to the propeller, which in turn drives the cooling air circulation. This self-powered approach eliminates the need for separate fans or external power sources, reducing energy consumption and mechanical complexity.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent ensures continuous cooling action by coupling the cooling system directly to the rotor's continuous rotational motion. As long as the wind drives the rotor, the propeller continuously circulates cooling air through the generator. This continuous useful action eliminates idle periods and maintains effective cooling throughout operation without requiring additional energy input.

Inventive Principle:
Principle #20Continuity of useful action

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 solution effectively increases cooling efficiency while minimizing corrosion risks, allowing for improved heat management and operational reliability in ring generators.

Implementation Method 1

wherein the fan is arranged to generate an overpressure in the pressure chamber in order to thereby generate an air flow through the stator and/or rotor

Methodology Applied
Scientific EffectPressure gradient: Pressure Gradient

Implementation Method 2

generate an air flow through the stator and/or rotor for cooling the ring generator

Methodology Applied
Scientific EffectForced convection: Forced Convection

Implementation Method 3

the stator ring having cooling channels for cooling the stator with an air flow

Methodology Applied
Scientific EffectConvection cooling: Forced Convection

Data Source

PatentEP2351191B2Ring generator
Publication Date: 2020.05.13 WOBBEN PROPERTIES GMBH
  • EP2351191B2 patent drawingFigure 1
  • EP2351191B2 patent drawingFigure 2
  • EP2351191B2 patent drawingFigure 3

AI summary

The invention relates to a ring generator of a wind turbine, comprising a stator ring having a rotating stator ring for accommodating stator windings and a rotor which is mounted so as to rotate about a rotational axis in relation to the stator, the stator ring comprising cooling channels for cooling the stator by means of an air current. The invention also relates to a ring generator of a wind turbine, comprising a stator, a rotating stator ring for receiving stator windings, a rotor which is mounted so as to rotate in relation to the stator and a stator bell which is connected to the stator ring to define an above or below atmospheric pressure compartment for making an air current available through and/or along the stator and/or rotor for cooling the ring generator, the stator bell comprising at least one blower opening having a blower and the blower being movably mounted by means of a motion mechanism to temporarily open the blower opening for the purpose of maintenance and/or for allowing a person to pass.