Wind Turbine Tower Damping via Adaptive Exclusion Zones
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Solution Overview
Problem
Conventional methods for damping oscillations in wind turbine towers either increase structural weight and cost or require large exclusion zones that negatively impact power production.
Innovation Solution
A method involving a wind turbine controller that determines a primary rotational frequency correlating to tower resonance and defines an exclusion zone, applying different damping force strategies below and above this zone to minimize oscillations, thereby reducing the need for large exclusion zones.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the structural strength of the wind turbine tower is increased by adding additional material, then the resonance frequency of the tower is moved outside of the operating frequency range, but the weight and costs of the wind turbine tower increase
Solution Approach 1:
The patent applies parameter changes by actively adjusting the rotational speed of the rotor to avoid the tower's resonance frequency. Instead of changing the physical parameters of the tower structure, the control system dynamically modifies the operational parameters (rotational speed) to prevent resonance conditions, thereby avoiding the need to add structural material.
Solution Approach 2:
The patent implements feedback control by continuously monitoring the tower's vibration levels and adjusting the rotor speed accordingly. The control system receives feedback about the tower's response and modifies the rotational speed to maintain operation outside the resonance frequency range, creating a closed-loop control system that adapts to varying conditions.
2Reliability
If a large exclusion zone is created where the rotor speed moves quickly through the tower resonance frequency, then tower oscillations are mitigated, but the negative impact on overall power production increases
Solution Approach 1:
The patent applies dynamics by making the exclusion zone adaptive rather than static. The control system dynamically adjusts the rotational speed and the boundaries of the exclusion zone based on real-time monitoring of tower vibrations and operational conditions. This allows the exclusion zone to be minimized when not needed and expanded only when resonance conditions are detected, optimizing both tower protection and power production.
Solution Approach 2:
The patent changes the parameter of exclusion zone size from a fixed large value to a dynamically adjusted value based on actual tower response. By monitoring vibration levels and adjusting the rotational speed profile, the system minimizes the width and duration of the exclusion zone, thereby reducing the impact on power production while still effectively mitigating tower oscillations when necessary.
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 approach effectively reduces tower oscillations while minimizing the negative impact on power production, achieving significant damping with a smaller exclusion zone compared to conventional methods.
Implementation Method 1
applying a first tower-damping force strategy... applying a second tower-damping force strategy
Data Source
AI summary
A method for damping oscillations in a tower of a wind turbine includes determining a primary rotational frequency of the rotor (fp) that correlates to a tower resonance frequency (fr). The method defines an exclusion zone between a first rotational frequency of the rotor (f1) that is less than the primary rotational frequency (fp) and a second rotational frequency of the rotor (f2) that is greater than the primary rotational frequency (fp). At rotor frequencies below the exclusion zone, a first tower-damping force strategy is applied. At rotor frequencies above the exclusion zone, a second tower-damping force strategy is applied that is different from the first tower-damping force strategy.