Wind Turbine Drive Train Torque Calibration Under Parasitic Loads
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Solution Overview
Problem
Existing methods for determining the efficiency and calibrating torque in wind turbine drive trains are inaccurate due to the lack of calibration options for high torques, and back-to-back tests do not accurately replicate real-world conditions, particularly in the presence of parasitic loads.
Innovation Solution
A method involving two tests on a drive train with different ends driven by drive units, using sensors to measure torque-dependent variables and calibrate based on assumptions from experiments, allowing for accurate efficiency determination and torque calibration across varying load conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If calibration devices from prior art are used for torque measurement, then the device complexity is reduced, but the measurement precision deteriorates because calibration is only possible up to 1.1 MNm while wind turbine torques reach several MNm
Solution Approach 1:
The patent inverts the traditional calibration approach by measuring torque at the output side (generator side) where lower torques occur, and then mathematically back-calculating the input side torque. This allows using standard calibration devices at the output while determining high-torque values at the input without requiring specialized high-torque calibration equipment.
Solution Approach 2:
The patent introduces a mechanical transmission element (gear unit) as an intermediary between the drive train and calibration devices. By placing torque sensors at the output of this transmission element where torques are reduced, standard calibration devices can measure with high precision, and the transmission ratio allows calculation of the original high torque values.
2Adaptability or versatility
If back-to-back tests with two gear units are used, then the adaptability to different test configurations is improved, but the measurement precision deteriorates because parasitic loads present in real wind turbines cannot be applied uniformly to both gear units
Solution Approach 1:
The patent extracts the parasitic load application from the dual gear unit system and applies it selectively to only one gear unit. This allows realistic simulation of wind turbine conditions where parasitic loads affect the drive train, while the other gear unit serves as a pure reference for efficiency measurement without contaminated loading conditions.
Solution Approach 2:
The patent segments the test configuration into two distinct roles: one gear unit serves as the test object with realistic parasitic loads, while the other serves as a reference unit without parasitic loads. This segmentation allows separate optimization of each unit's function in the test setup, improving both adaptability and measurement precision.
Data Source
AI summary
A method and device for ascertaining drive train efficiency includes performing first and second tests on a drive train having first and second shaft portions driven by respective drive devices and connected by a mechanical transfer element. The method includes detecting torque-dependent variables at both shaft portions during each test while driving one end and measuring corresponding variables at the opposite end. The drive train efficiency is determined based on one or more of: a power determined during the first and the second test, a variable dependent on the torque acting on the first shaft portion and on the second shaft portion during the first and second test, and at least one predetermined criterion.