Wind Turbine Rotor Control for Edgewise Vibration Reduction

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Solution Overview

Problem

Wind turbines experience undesirable edgewise vibrations, which are poorly damped and can lead to blade damage, requiring either shutdowns or active pitching to mitigate, but existing solutions are not sufficient to effectively reduce these vibrations without impacting output.

Innovation Solution

A rotor control system that applies a pitch modification signal to pitch-adjustable blades based on an m-blade coordinate transformation and filtering, creating a moment to attenuate edgewise vibrations by transforming and filtering edgewise load signals between rotating and whirling reference frames.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the wind turbine is shut down to eliminate harmful edgewise vibrations, then blade damage is prevented, but the overall output of the wind turbine is reduced

Engineering Contradiction:

Improveblade damage preventionVSAvoidwind turbine output

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The patent converts the harmful edgewise vibrations into a useful control signal by measuring the vibration level and using it to adjust the pitch angle. The vibration measurement, which would normally indicate damage risk, is transformed into a control input that actively counteracts the vibrations, converting a harmful indicator into a beneficial control parameter.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The patent implements a feedback control system where the edgewise vibration level is continuously measured and fed back to the pitch control system. The pitch angle is adjusted based on the measured vibration level, creating a closed-loop system that actively suppresses vibrations while maintaining turbine operation.

Inventive Principle:

Principle #23Feedback

2Reliability

If active pitching is applied to dampen edgewise vibrations, then blade vibrations are reduced, but the complexity of the control system increases

Engineering Contradiction:

Improvevibration dampingVSAvoidcontrol system complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent makes the pitch control system multi-functional by enabling it to perform both its traditional function of optimizing power production and its additional function of suppressing edgewise vibrations. The same pitch actuation mechanism serves dual purposes, eliminating the need for separate vibration damping hardware.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent changes the control parameter from fixed pitch angles to dynamically adjusted pitch angles based on measured vibration levels. By making the pitch angle a variable parameter that responds to real-time vibration conditions, the system achieves effective vibration damping without requiring complex additional control mechanisms.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS12135012B2Reduction of edgewise vibrations using blade load signal

Publication Date: 2024.11.05 VESTAS WIND SYSTEMS AS

AI summary

The present invention relates to a rotor control system for actuating pitch of pitch adjustable rotor blades of a wind turbine in order to reduce edgewise blade vibrations. The system comprises a pitch actuation unit being arranged to receive an edgewise load signal and apply m-blade coordinate transformations, such as the Coleman transformations, to the edgewise load signal. Based on a selected signal component at either a backward whirling frequency or a forward whirling frequency, a modified modification signal is obtained.