Wind Turbine Rotor Static Imbalance Detection
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Solution Overview
Problem
Current methods for determining static mass imbalance in wind turbine rotors are inefficient, often requiring shutdown and are not reliable for in-situ detection during operation, leading to potential premature bearing damage and noise issues due to speed-dependent excitations.
Innovation Solution
A method that measures location-dependent angular acceleration and torque during rotor revolution, using trigonometric functions to determine the imbalance by analyzing the amplitude and phase shift of the resulting trigonometric function, allowing for online detection during operation without decoupling from the grid, and continuously monitoring changes in imbalance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional methods for determining static mass imbalance are used, then the rotor must be shut down for measurement, but this leads to increased downtime and production losses
Solution Approach 1:
The measurement system utilizes the rotor's own operational data (angular acceleration and torque during normal rotation) to determine imbalance, eliminating the need for external balancing equipment and shutdown procedures. The rotor essentially measures itself during regular operation.
Solution Approach 2:
The imbalance determination is performed continuously during rotor operation rather than requiring shutdown. The system processes operational data in real-time, allowing the rotor to maintain its useful function (generating power) while simultaneously undergoing measurement.
2Measurement precision
If the rotor is shut down for imbalance measurement, then accurate determination can be achieved, but this reduces productivity
Solution Approach 1:
The system enables simultaneous production and measurement by processing operational data during normal rotor operation. The generator continues to produce electricity while the control device analyzes angular acceleration and torque data to determine imbalance.
Solution Approach 2:
The operational data required for measurement is obtained from the rotor's own operation rather than requiring separate measurement procedures. The system uses the rotor's natural operational characteristics (speed fluctuations, torque variations) as the measurement input.
3Loss of time
If online measurement during operation is implemented, then downtime is reduced, but the complexity of the measurement system increases
Solution Approach 1:
The control device performs multiple functions: it controls the generator operation, monitors operational parameters, and determines imbalance. This multi-functionality eliminates the need for separate dedicated measurement equipment, reducing overall system complexity despite the advanced capabilities required.
Solution Approach 2:
The control device acts as an intermediary that processes existing operational data (angular acceleration from speed measurements and torque from power calculations) to extract imbalance information. Rather than requiring direct physical measurement of imbalance forces, the system uses mathematical processing of readily available operational parameters.
4Measurement precision
If traditional offline calibration methods are used, then measurement accuracy can be ensured, but this requires decoupling from the grid and causes production losses
Solution Approach 1:
The system maintains continuous grid connection and power production during the measurement process. The generator remains coupled to the grid while operational data is collected and processed, ensuring uninterrupted electricity generation and avoiding production losses associated with decoupling.
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
Enables simple and reliable determination of static imbalance during wind turbine operation, reducing downtime and production losses, and improving rotor efficiency by allowing for real-time correction of imbalances, thus extending component lifespan and reducing maintenance.
Implementation Method 1
a rotor with a known mass moment of inertia and a known axis of rotation in an external force field, in particular in the gravitational field of the earth
Implementation Method 2
Circumferential centrifugal forces implied by imbalance can, for example, lead to premature bearing damage
Implementation Method 3
A moment of inertia is determined as the product of angular acceleration and mass moment of inertia
Data Source
Figure 1
Figure 2~3
AI summary
A method for determining a static imbalance (110) of a rotor (103) of a wind turbine (100), wherein the rotor (103) has a known moment of inertia and an axis of rotation (111), comprises: - determining a location-dependent angular acceleration and a location-dependent torque as a function of the angle of rotation (107) during one rotor revolution; - determining a moment of inertia as the product of angular acceleration and moment of inertia; - adding the determined moment of inertia and the determined torque to obtain a location-dependent total torque; - determining a trigonometric function from the location-dependent total torque; - Determining the imbalance (110) that has a mass at a distance (112) from the axis of rotation (111) of the rotor (103) and an angle (114), as a function of the amplitude (115) and the phase shift (116) of the determined trigonometric function.