Wind Turbine Tower Damping via Rotor Speed Feedback Control

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Solution Overview

Problem

Wind turbines with taller towers, which are beneficial for greater power production, face instability due to dynamic interactions between tower movement and rotor speed, leading to challenges in controlling power production effectively.

Innovation Solution

A method and controller that determine dynamic state information, including tower frequency, to calculate control loop gain values, generating control signals for rotor speed control, thereby mitigating instability and allowing for more aggressive tuning of wind turbines for increased power production.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If taller towers are used to support larger diameter rotors and reduce ground effects, then power production increases, but tower flexibility increases causing dynamic interactions and control instability

Engineering Contradiction:
Improvepower productionVSAvoidcontrol stability
Core Design Contradiction:
ProductivityVSStability of the object's composition

Solution Approach 1:

The patent implements a feedback control mechanism where tower motion is measured by sensors (accelerometers, gyroscopes, or position sensors) and this information is fed back to the controller. The controller adjusts rotor speed or blade pitch in real-time to counteract tower motion, thereby stabilizing the system despite the flexibility of taller towers. This closed-loop feedback enables the system to maintain control stability while utilizing taller towers for increased power production.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent dynamically changes control parameters (such as rotor speed reference or blade pitch angle) based on measured tower motion states. When tower motion is detected, the controller modifies operational parameters to compensate for the dynamic interactions, allowing the system to adapt to varying tower flexibility conditions and maintain stable control across different tower heights and operating conditions.

Inventive Principle:
Principle #35Parameter changes

2Use of energy by moving object

If tower height is increased to support larger rotors, then energy capture improves, but dynamic interactions between tower motion and rotor speed create instability

Engineering Contradiction:
Improveenergy captureVSAvoidcontrol reliability
Core Design Contradiction:
Use of energy by moving objectVSReliability

Solution Approach 1:

The system continuously monitors tower motion through sensors and feeds this information back to the controller, which adjusts rotor speed or pitch in real-time. This feedback loop ensures reliable control by compensating for dynamic interactions caused by tower flexibility, maintaining system reliability even with taller towers that capture more energy.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent employs dynamic control strategies where control parameters are continuously adjusted based on real-time tower motion measurements. The controller adapts rotor speed references or blade pitch angles dynamically to account for varying tower flexibility and operating conditions, ensuring reliable control while maximizing energy capture from taller tower configurations.

Inventive Principle:
Principle #15Dynamics

3Ease of operation

If blade pitching is used to control power production by counteracting aerodynamic torque, then power control is achieved, but forces on the tower change affecting tower motion and creating dynamic interactions

Engineering Contradiction:
Improvepower controlVSAvoiddynamic interactions
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent merges the tower motion damping function with the existing power control system by integrating tower motion measurements into the rotor speed or pitch control loops. Rather than adding a completely separate control system, the tower damping functionality is combined with the power production control, allowing simultaneous management of power output and tower stability through a unified control approach.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The control system is designed to perform multiple functions: it simultaneously controls power production through blade pitching and dampens tower motion through coordinated rotor speed or pitch adjustments. This multi-functional control approach reduces overall system complexity by using a single integrated controller to manage both power control and tower stabilization objectives.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentEP3724488B1Tower damping during power production of a wind turbine
Publication Date: 2023.02.01 VESTAS WIND SYSTEMS AS
  • EP3724488B1 patent drawingFigure 1
  • EP3724488B1 patent drawingFigure 2
  • EP3724488B1 patent drawingFigure 3

AI summary

A method for wind turbine tower damping is disclosed, as well as an associated controller and wind turbine. The method comprises determining, using one or more sensor signals, dynamic state information for a tower of a wind turbine during power production, wherein the dynamic state information comprises a tower frequency. The method further comprises determining at least one control loop gain value using the tower frequency, and generating, using the at least one control loop gain value, one or more control signals for controlling a rotational speed of a rotor of the wind turbine.