Wind Turbine Blade Deflection Monitoring with Sensor Fusion

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Solution Overview

Problem

Current wind turbine blade deflection monitoring systems face challenges such as limited sensor lifespan, vulnerability to handling damage, drift issues with integrated accelerometer data, and susceptibility to lightning damage, making it difficult to accurately estimate blade deflection in real-time and prevent tower strikes.

Innovation Solution

A wind turbine blade deflection monitoring system with sensors mounted at different radial positions along the blade, comprising accelerometers and magnetic transducers, encapsulated in a metallic shield for lightning protection, and combined with other transducers to estimate both average and absolute blade deflection, allowing for control actions to prevent strikes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If accelerometers are used for blade deflection monitoring, then robustness is improved, but position accuracy deteriorates due to integration drift

Engineering Contradiction:
ImproverobustnessVSAvoidposition accuracy
Core Design Contradiction:
StrengthVSMeasurement precision

Solution Approach 1:

The patent combines multiple sensor types (accelerometers, magnetic sensors, and other transducers) into an integrated monitoring system. This merging allows the system to leverage the robustness of accelerometers while compensating for their integration drift through data fusion with other sensors, thereby maintaining both robustness and measurement accuracy.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent introduces magnetic sensors and other transducers as intermediary elements that provide alternative measurement pathways. These intermediary sensors do not suffer from the same integration drift issues as accelerometers and serve to correct or supplement the accelerometer data, improving overall position accuracy while maintaining system robustness.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If optical strain gauges are used for blade deflection monitoring, then measurement precision is improved, but reliability deteriorates due to vulnerability to handling damage

Engineering Contradiction:
Improvedeformation measurement accuracyVSAvoidsensor durability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent employs magnetic sensors and other robust transducers that can be made more durable and less susceptible to handling damage compared to optical strain gauges. While these alternative sensors may have different measurement characteristics, they provide reliable long-term operation in the harsh wind turbine environment.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent creates a composite sensing system that integrates multiple sensor types with complementary strengths. By combining sensors with different operational characteristics and durability profiles, the system achieves both adequate measurement precision and improved reliability through the composite nature of the monitoring apparatus.

Inventive Principle:
Principle #40Composite materials

3Measurement precision

If GPS sensors are used for blade deflection monitoring, then position accuracy is improved, but reliability deteriorates due to vulnerability to lightning damage

Engineering Contradiction:
Improveposition information accuracyVSAvoidlightning protection
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent extracts the position measurement function from GPS sensors that require external antennas vulnerable to lightning, and implements it instead using magnetic sensors and other transducers mounted directly on the blade. This extraction eliminates the lightning vulnerability while maintaining the ability to provide accurate position information for blade deflection monitoring.

Inventive Principle:
Principle #2Taking out (Extraction)

4Measurement precision

If magnetic sensors are used for blade deflection monitoring, then position accuracy is improved, but device complexity increases due to calibration requirements

Engineering Contradiction:
Improveposition information accuracyVSAvoidcalibration complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent implements self-calibration or automatic calibration routines for magnetic sensors, allowing the system to compensate for drift and environmental effects without requiring manual intervention. This self-service approach reduces the operational complexity and maintenance burden while preserving the high position accuracy that magnetic sensors provide.

Inventive Principle:
Principle #25Self-service

5Strength

If blade pitch angle and rotor speed are adjusted for control, then blade deflection can be limited, but loss of energy increases due to reduced power output

Engineering Contradiction:
Improveblade deflection controlVSAvoidpower output reduction
Core Design Contradiction:
StrengthVSLoss of energy

Solution Approach 1:

The patent implements a feedback control system that continuously monitors blade deflection using multiple sensors and adjusts blade pitch angle and rotor speed in real-time. This closed-loop feedback allows for precise control of blade deflection while minimizing energy loss by making only the necessary adjustments to maintain safe operating conditions, rather than conservative pre-limiting of power output.

Inventive Principle:
Principle #23Feedback

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

The system provides accurate real-time blade deflection monitoring, reducing the risk of tower strikes and excessive strain by combining sensor data with wind and rotor parameters, while being protected against lightning damage and ensuring robust operation.

Implementation Method 1

each sensor comprises an accelerometer and/or a magnetic transducer in addition to any other transducers included in the sensor

Methodology Applied
Scientific EffectAccelerometer: Accelerometer

Implementation Method 2

each sensor comprises an accelerometer and/or a magnetic transducer in addition to any other transducers included in the sensor

Methodology Applied
Scientific EffectMagnetic transducer: Magnetic Field

Data Source

PatentEP3732372B1Wind turbine blade deflection monitoring system and method for the monitoring of wind turbine blade deflection
Publication Date: 2024.11.13 STIESDAL OFFSHORE TECH AS
  • EP3732372B1 patent drawingFigure 1~2
  • EP3732372B1 patent drawingFigure 3~4

AI summary

The system comprises two or more sensors mounted in the wind turbine blade, each sensor comprising an accelerometer and/or a magnetic transducer. The sensors and their connectors are jointly encapsulated in a protective cover covered with a metallic shield. Blade deflection comprises the steps of estimating the variations around the average wind turbine blade deflection based on the signals from the sensors, estimating the average wind turbine blade deflection from calculations based on a combination of measured operational parameter, and estimating the absolute value of the blade deflection by combining the estimate of the variations around the average blade deflection with the estimate of the average blade deflection.