Wind Turbine Load Control with Smooth Damage-Rate Mode Transitions

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Solution Overview

Problem

Existing wind turbine control methods fail to effectively reduce loads during severe conditions while minimizing power production loss, as they either rely on accumulated load calculations or abrupt transitions between operating modes, neglecting structural surplus and not accounting for short-term extreme loads.

Innovation Solution

A control method that measures load signals, calculates a real-time damage rate, and adjusts operations between normal and safe modes by applying control actions based on normalized damage rates, allowing gradual transitions and reducing loads while limiting power production loss by utilizing structural surplus and detecting both short-term and long-term loads.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the wind turbine is shut down or positioned in parked mode during extreme wind conditions, then the loads on the wind turbine are minimized, but the power production is completely lost

Engineering Contradiction:
Improveload reductionVSAvoidpower production
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The control method dynamically adjusts the operating mode between normal and reduced power modes based on real-time damage rate calculations. Instead of static shutdown decisions, the system continuously monitors load signals, calculates damage rates using fatigue analysis, and transitions between operating states to optimize both load protection and power production.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes operational parameters (power production level, rotor speed, pitch angle) based on the calculated damage rate. When the damage rate exceeds thresholds, the system transitions to a reduced power mode with adjusted parameters that maintain safety while preserving some power generation capability.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If the wind turbine operates in normal mode continuously, then the power production is maximized, but the structural component may fail under severe loads

Engineering Contradiction:
Improvepower productionVSAvoidstructural integrity
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The control method implements a feedback mechanism where load signals from sensors are continuously measured, damage rates are calculated based on fatigue analysis of these signals, and the operating mode is adjusted according to the calculated damage rate. This closed-loop feedback ensures structural integrity is maintained while maximizing power production within safe limits.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system performs preliminary damage rate calculations and threshold comparisons before transitioning to protective modes. By continuously monitoring and calculating damage rates in advance, the system can take preventive action before structural failure occurs, rather than reacting after damage has accumulated.

Inventive Principle:
Principle #10Preliminary action

3Reliability

If the control method uses accumulated load calculations, then the long-term structural damage is considered, but the short-term extreme loads are not detected in real-time

Engineering Contradiction:
Improvelong-term structural assessmentVSAvoidresponse time
Core Design Contradiction:
ReliabilityVSSpeed

Solution Approach 1:

The control method segments the damage rate calculation into distinct components: accumulated load cycles for long-term assessment and real-time damage rate for short-term detection. This segmentation allows the system to simultaneously consider both historical fatigue data and current loading conditions, enabling both long-term reliability assessment and immediate response to extreme loads.

Inventive Principle:
Principle #1Segmentation

4Reliability

If the wind turbine transitions abruptly between operating modes, then the load protection is immediate, but the power production loss is maximized

Engineering Contradiction:
Improveload protection speedVSAvoidpower production
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The control method implements dynamic, gradual transitions between operating modes rather than abrupt switches. The transition is controlled based on the rate of change of the damage rate, allowing the system to respond quickly to dangerous conditions while minimizing unnecessary power production losses during moderate loading scenarios.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP3317529B1Method for controlling loads on a wind turbine and wind turbine
Publication Date: 2021.05.05 ENVISION ENERGY DENMARK
  • EP3317529B1 patent drawingFigure 1
  • EP3317529B1 patent drawingFigure 2~6
  • EP3317529B1 patent drawingFigure 7~8

AI summary

The present invention relates to a control method and a wind turbine configured to determine a load signal of at least one component of the wind turbine, and to calculate a damage rate based on this load signal. The control method calculates and monitors the damage rate in real-time, wherein the damage rate is normalised by using a first function defining a first transition phase. A second function is afterwards applied to the normalised damage rate which defines a second transition phase. These transition phases allows for a smooth transition between different operating modes of the wind turbine. The control method may further change the power output of the wind turbine relative to the nominal power output when the output signal of the second function is determined to be stable over at least one time period.