Wind Turbine Tower Bending Moment Measurement for Thrust Control

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Solution Overview

Problem

Current wind farm planning and operation are limited by turbulence in the wake of wind turbines, leading to reduced energy yield and potential damage, as existing methods struggle to accurately determine and control turbulence, resulting in excessive spacing between turbines and reduced farm performance.

Innovation Solution

A measuring arrangement for wind turbines that includes sensors at different heights to detect bending moments, allowing for the determination of thrust force and shear force, which is used to assess and control turbulence, enabling precise regulation of wind turbine operation to minimize wake turbulence.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If multiple sensors are distributed over multiple locations on the rotor blade to determine blade moment, then measurement precision is improved, but device complexity increases

Engineering Contradiction:
Improveblade moment measurement precisionVSAvoidsensor distribution complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts the measurement function from multiple distributed sensors on rotor blades and concentrates it into a single measurement arrangement on the tower. By measuring bending moments at two different tower heights, the system determines thrust force without requiring multiple sensors on the rotor blade, thus reducing device complexity while maintaining measurement precision

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The tower acts as an intermediary structure that transmits the thrust force effects from the rotor to the measurement sensors. Instead of measuring directly on the rotor blade, the bending moments in the tower at different heights serve as intermediate measurements that allow indirect determination of thrust force with a single measurement arrangement

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If minimum distance between wind turbines is increased to account for wake turbulence, then reliability is improved, but productivity decreases

Engineering Contradiction:
Improvewind turbine operation reliabilityVSAvoidenergy yield per area
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent implements a feedback mechanism where thrust force is continuously determined from tower bending moments and used to control the wind turbine operation. By actively controlling thrust force based on real-time measurements, the system can maintain reliable operation while reducing the need for excessive spacing between turbines, thus improving productivity

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The measurement and control system enables dynamic adjustment of wind turbine operation based on actual thrust force conditions rather than static safety margins. This allows the system to adapt to varying wind conditions and maintain reliable operation with optimized spacing, improving energy yield per area

Inventive Principle:
Principle #15Dynamics

3Reliability

If safety margin is applied in wind farm planning to account for turbulence, then reliability is improved, but loss of information occurs

Engineering Contradiction:
Improvewind farm operation reliabilityVSAvoidactual turbulence conditions information
Core Design Contradiction:
ReliabilityVSLoss of information

Solution Approach 1:

The patent replaces simulation-based turbulence assessment with direct physical measurement of thrust force through tower bending moment measurements. This substitution provides actual turbulence conditions information rather than relying on simulated data with applied safety margins, eliminating information loss while maintaining reliability

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 solution allows for more accurate determination and control of turbulence, enabling closer spacing of wind turbines, increased energy output per area, and enhanced safety by reducing the impact of turbulence on other turbines, even in unforeseen wind conditions.

Implementation Method 1

a measuring device set up to detect a first bending moment of the tower at a first height and a second bending moment of the tower at a second height

Methodology Applied
Scientific EffectBending moment measurement:

Data Source

PatentEP3500752B1Measurement arrangement of a wind turbine
Publication Date: 2021.01.27 WOBBEN PROPERTIES GMBH
  • EP3500752B1 patent drawingFigure 1
  • EP3500752B1 patent drawingFigure 2
  • EP3500752B1 patent drawing

AI summary

The invention relates to a measurement arrangement for a wind turbine (100) in order to determine a thrust (220) of the rotor. A measurement apparatus detects a first bending moment of the tower (102) at a first height and a second bending moment of the tower (102) at a second height different from the first height. In that context, the first and second bending moments each consist of a natural moment component, a pitching moment component and a thrust component. A thrust-determining unit determines a thrust (220) of the rotor (106) on the basis of a comparison of the at least one first and second bending moments, thus eliminating the natural moment component and the pitching moment component.