Wind Turbine Rotor Speed Estimation Using Gyro-Accelerometer Feedback
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Solution Overview
Problem
Existing methods for determining wind turbine rotor speed, particularly in the safety domain, are prone to noise sensitivity, require expensive equipment, and suffer from communication breakdowns and inaccuracies due to DC offset and drift in gyroscope measurements, necessitating verification against nacelle-based measurements.
Innovation Solution
A method using a combined angular velocity and acceleration sensor system in the rotor hub, transforming data into a rotational coordinate system, compensating for centripetal forces, and applying correction values to improve accuracy, enabling hub-based rotor speed estimation without nacelle communication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If gyroscope-based rotor speed measurement is used in the rotor hub, then hub-based measurement capability is provided, but measurement accuracy deteriorates due to DC offset and drift
Solution Approach 1:
The system uses feedback by continuously comparing the gyroscope-based rotor speed measurement with the accelerometer-based rotor speed measurement, and applying correction values to compensate for DC offset and drift in the gyroscope signal, thereby maintaining measurement accuracy
Solution Approach 2:
The accelerometer serves as an intermediary measurement device that provides an independent method for determining rotor speed, which is then used to correct the gyroscope measurement and eliminate the harmful effects of DC offset and drift
2Measurement precision
If nacelle-based rotor speed measurement is used for verification, then measurement accuracy can be maintained, but communication dependency increases
Solution Approach 1:
The rotor hub becomes self-sufficient by incorporating both gyroscope and accelerometer sensors that can independently determine rotor speed, eliminating the need for communication with the nacelle for verification and enabling autonomous operation even when communication fails
3Measurement precision
If pulse train signal comparison method is used, then rotor speed can be measured, but noise sensitivity increases particularly at low speeds
Solution Approach 1:
The system replaces the mechanical/pulse-based speed sensor comparison method with inertial sensing using gyroscopes and accelerometers, which provide continuous analog measurements that are less susceptible to noise and can operate effectively at low rotor speeds
4Reliability
If multiple separate measurement systems are used for control and safety domains, then comprehensive monitoring is achieved, but device complexity increases
Solution Approach 1:
The system merges the control domain and safety domain measurement capabilities into a single integrated sensor package in the rotor hub, containing both gyroscope and accelerometer sensors that provide rotor speed measurements for both control and safety functions, thereby reducing overall system complexity
Solution Approach 2:
The integrated sensor system in the rotor hub serves multiple functions - providing rotor speed measurements for both control domain operations and safety domain monitoring, eliminating the need for separate measurement systems and reducing complexity
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
Provides accurate and robust rotor speed measurement resilient to noise and communication breakdowns, reducing costs and complexity while maintaining dynamic response and reliability.
Implementation Method 1
an angular velocity sensor (e.g. a gyroscope) in the rotor hub for measuring an angular velocity of the rotor hub
Implementation Method 2
an acceleration sensor in the rotor hub for measuring an acceleration of the rotor hub
Data Source
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AI summary
The invention relates to determining rotor speed of a wind turbine The invention involves receiving angular velocity sensor data indicative of an angular velocity of the wind turbine rotor hub, provided e.g. by a gyroscope, and receiving acceleration sensor data indicative of an acceleration of the rotor hub in at least one radial direction relative to an axis of rotation of the rotor hub. The invention involves determining first and second estimated rotational speeds of the rotor hub based on the respective angular velocity sensor data and acceleration sensor data. The invention involves determining a correction value based on a difference between the first and second estimated rotational speeds, and applying the correction value to the first estimated rotational speed to determine the true current rotor speed of the wind turbine.