Wind Turbine Rotor Position Correction via Impulse Reference
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Solution Overview
Problem
The calibration of rotary encoders in wind turbines is challenging, especially when gearbox changes occur without recalibration, leading to rotor position errors that cause asymmetrical load control and decreased energy production due to difficulties in adjusting the low speed shaft/rotor-position-encoder coupling.
Innovation Solution
A method involving an impulse generating device with rotating and stationary parts, where the rotary encoder encodes the azimuth angle and generates impulses, allowing for comparison with reference values to correct rotor position errors, implemented in a wind turbine control system to prevent load imbalances and maintain energy production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the rotary encoder is fixed to the low speed shaft by coupling, then the encoder can measure the rotor position, but the coupling is difficult to adjust and becomes a potential source of referencing errors
Solution Approach 1:
The patent introduces an intermediary impulse generating device with stationary parts that interact with rotating parts to generate reference impulses. This mediator system decouples the direct mechanical connection between the encoder and rotor, allowing the encoder to be mounted on the stationary housing while still measuring rotor position through the impulse reference system.
Solution Approach 2:
The patent replaces the mechanical coupling-based encoder mounting with an optical/electronic impulse generation system. Instead of mechanically coupling the encoder to the rotor shaft, the system uses optical or magnetic sensors to detect impulses from rotating features, eliminating the difficult-to-adjust mechanical coupling.
2Productivity
If the gearbox is changed without recalibration of the rotary encoder, then the gearbox can be replaced for maintenance or upgrade, but rotor position errors cause asymmetrical load control and significantly increase turbine loads
Solution Approach 1:
The patent implements a self-calibrating system where the impulse generating device automatically provides reference impulses that enable the control system to self-correct rotor position measurements. The system continuously compares encoder readings with impulse reference signals and automatically adjusts for positional drift, eliminating the need for manual recalibration after gearbox changes.
Solution Approach 2:
The patent introduces a feedback mechanism where the control device continuously monitors the relationship between encoder readings and impulse reference signals. When position drift is detected, the system generates correction signals to compensate for the error, ensuring accurate load control without requiring physical recalibration of the encoder.
3Duration of action of stationary object
If the rotary encoder is not calibrated, then the system can operate without interruption, but the rotor position error decreases the annual energy production of the wind turbine
Solution Approach 1:
The patent ensures continuous accurate operation by implementing a reference impulse system that continuously validates and corrects encoder readings. The impulse generating device operates continuously to provide reference signals, enabling the system to maintain accurate rotor position measurement without interruption or periodic recalibration, thus sustaining optimal energy production continuously.
Data Source
AI summary
The disclosure relates to a method for controlling a wind turbine including a wind rotor shaft, a rotary encoder for measuring the azimuth angle of the wind rotor shaft, wherein the wind turbine further includes at least one impulse generating device including at least one first part and at least one second part, wherein the at least one first part is rotating with the wind rotor shaft and the least one second part is disposed stationary with respect to the wind rotor shaft such that the at least one first part moves by the at least one second part; wherein the method includes: encoding the azimuth angle of the wind rotor shaft by the rotary encoder into a rotation value; generating an impulse when one of the at least one first part moves by one of the at least one second part of the impulse generating device; comparing the rotation value at the time of a detected impulse with a reference value.