Infrared Camera Inspection of Wind Turbine Generator Stator Welds

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Solution Overview

Problem

The challenge lies in quickly, cheaply, and reliably testing the numerous welded connections of a generator stator in wind turbines, as visual inspection is complex and time-consuming, especially with the increasing size of generators, and traditional methods are costly and prone to errors.

Innovation Solution

A method utilizing one or more infrared cameras positioned along circular lines to capture images of welded connections, with image processing techniques to detect temperature differences caused by exciting the windings, allowing for efficient identification of faulty connections without the need for extensive post-processing or multiple cameras.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If visual inspection of welded joints is performed manually, then inspection reliability can be maintained, but inspection time increases significantly due to the large number of welded joints (more than 1000)

Engineering Contradiction:
Improveinspection reliabilityVSAvoidinspection time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent replaces manual visual inspection with an automated optical inspection system using cameras and image processing algorithms. The system automatically captures images of welded joints, processes them through software algorithms, and identifies defects without human intervention, thereby maintaining inspection reliability while dramatically reducing inspection time for the large number of welded joints in wind turbine generators

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the inspection parameter from manual visual assessment to automated image analysis with specific evaluation criteria. By defining quantitative parameters for weld quality assessment and using algorithms to evaluate these parameters automatically, the system maintains consistent reliability standards while enabling high-speed processing of numerous welded joints

Inventive Principle:
Principle #35Parameter changes

2Reliability

If multiple cameras are used to inspect the entire generator stator, then inspection completeness improves, but system cost and complexity increase

Engineering Contradiction:
Improveinspection completenessVSAvoidsystem complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent divides the inspection task into segments by grouping welded joints according to their radial distance from the center point of the generator stator. This segmentation allows the inspection system to process different groups of welds systematically, ensuring complete coverage of all welded joints while using a manageable number of cameras positioned to capture specific radial zones

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces a radial dimension for organizing and inspecting welded joints by grouping them at different radial distances from the center point. This dimensional approach allows the system to methodically cover the entire stator surface area, ensuring inspection completeness while optimizing camera placement and reducing the total number of cameras needed compared to a comprehensive multi-camera array

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

3Weight of moving object

If aluminum coils are used instead of copper coils, then weight advantage is achieved, but welding reliability decreases due to aluminum's soft material properties

Engineering Contradiction:
Improvecoil weightVSAvoidwelding reliability
Core Design Contradiction:
Weight of moving objectVSReliability

Solution Approach 1:

The patent replaces manual welding quality assessment with automated optical inspection using image capture and analysis systems. This substitution enables reliable detection and evaluation of aluminum weld quality without being affected by the soft material properties of aluminum, thereby maintaining welding reliability while allowing the use of lightweight aluminum coils instead of copper coils

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 a cost-effective, quick, and reliable inspection of welded connections by using a minimal number of cameras, reducing the complexity and cost of the inspection process while effectively distinguishing between correct and incorrect welds based on thermal imaging.

Implementation Method 1

one or more cameras, in particular infrared cameras

Methodology Applied
Scientific EffectInfrared radiation detection: Infrared Radiation

Implementation Method 2

temperature differences caused by exciting the windings

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Data Source

PatentEP3988929A1Method for testing a welding connection of a generator stator of a wind power installation and holder for carrying out the method and system with the holder
Publication Date: 2022.04.27 WOBBEN PROPERTIES GMBH
  • EP3988929A1 patent drawingFigure 1
  • EP3988929A1 patent drawingFigure 2~3
  • EP3988929A1 patent drawingFigure 4~5b

AI summary

The invention relates to a method for inspecting a welded joint (56) of a generator stator (10), in particular of a wind turbine (100), comprising the steps of providing a generator stator (10) with one or more groups of welded joints (56), wherein the welded joints (56) of each group have, in particular, a substantially equal radial distance from a point (36) of an axis (38) of the generator stator (10); providing one or more cameras (22), in particular infrared cameras; defining a circle (32, 34) for the camera (22) or for each of the cameras (22), wherein the circle (32, 34) or circles (32, 34) each have a center point (36) through which the axis (38) of the generator stator (10) passes; and moving the one or more cameras (22) to several different recording positions (26) of the camera on the circle (32, 34) assigned to the camera (22). 34) or,wherein all recording positions (26) of each of the cameras (22) lie on the circular line (32, 34) assigned to the respective camera (22). The invention further relates to a holder (16) and a system (14).