Wind Turbine Blade Deflectable Flap Load Control
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Solution Overview
Problem
Existing wind turbines face challenges in accurately controlling blade loads, especially at high wind speeds and with varying wind conditions, as traditional pitch control methods and other proposed solutions like Gurney flaps or active geometry control do not fully optimize blade loading and can be prone to noise or damage from lightning.
Innovation Solution
The implementation of rotor blades with deflectable flaps controlled by fluid inflatable means, allowing for precise adjustment of airflow over the blades based on load, velocity, and flow measurements, using flexible materials and fairing plates to optimize blade loads and minimize pitch activity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If Gurney flaps are attached to the trailing edge for optimizing blade loads, then blade loading is improved, but aerodynamic noise increases from the free ends and gaps
Solution Approach 1:
The invention extracts the load optimization function from traditional Gurney flaps by using a deflectable flap that can be actively controlled. The flap is integrated into the blade structure with a hinge connection, allowing it to be deployed only when needed for load optimization while retracting to minimize noise generation during normal operation.
Solution Approach 2:
The invention applies dynamics by making the flap deflectable and controllable through actuation means. The flap can dynamically adjust its position based on operating conditions, being deflected to optimize blade loads during high wind speeds and retracted during normal conditions to minimize aerodynamic noise from free ends.
2Productivity
If piezoelectric plates are built in the trailing edge for modifying geometry to reduce blade loads, then blade load control is improved, but reliability decreases due to electrical cables being vulnerable to lightning
Solution Approach 1:
The invention replaces the electrical piezoelectric system with a mechanical actuation system. The flap is controlled by mechanical actuators (such as shape memory alloys, piezomagnetic materials, or hydraulic/pneumatic systems) that do not require electrical cables penetrating the blade structure, thereby eliminating the lightning vulnerability associated with electrical cable systems.
Solution Approach 2:
The invention introduces an intermediary actuation mechanism between the control system and the flap. Instead of directly using electrical cables connected to piezoelectric elements, a mechanical intermediary (actuator) is used to transmit the control signal to the flap, isolating the electrical components from the external environment and lightning strikes.
3Force
If pitch control is used to reduce dynamic loads at high wind speeds, then blade load reduction is achieved, but control precision decreases because blade loading varies over blade length
Solution Approach 1:
The invention segments the blade into multiple zones with independent control capabilities. By placing multiple flaps at different spanwise positions along the blade, each flap can be independently controlled to address local loading conditions, providing precise control of blade loads throughout the entire blade length rather than uniform pitch control.
Solution Approach 2:
The invention applies local quality by making the flap characteristics and control parameters location-dependent. Each flap's deflection angle, size, and actuation force can be independently adjusted based on the specific loading conditions at its spanwise position, allowing optimized local control precision for varying blade loads along the blade length.
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 enables more accurate control of blade loads and improved rotor performance by dynamically adjusting the airflow, reducing the need for excessive pitch adjustments and minimizing aerodynamic noise and damage risks.
Implementation Method 1
geometry changing means comprising a flexible tube extending along the spanwise direction of the flap which is arranged inside a chamber and is inflatable with a fluid
Data Source
Figure 1~3
AI summary
A wind turbine having at least a blade comprising a first component (11) having an aerodynamic profile with a leading edge, a trailing edge and suction and pressure sides between the leading edge and the trailing edge, and a second component (13), attached to the trailing edge and/or to the leading edge of the first component (11) in at least a part of the blade, comprising an upwards and/or downwards deflectable flap (15) that allows changing the flow over the blade, in which the means for deflecting the flap (15) are fluid inflatable means (23) placed in a flap inner chamber (25) close to the first component (11) and in which the wind turbine comprises means for controlling said inflatable means (23) depending on the wind situation and/or the blade loads.