Wind Turbine Blade Angle Control for Gust Response
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Solution Overview
Problem
Wind energy installations face issues with overspeed due to gusty winds, leading to unnecessary emergency shutdowns, as the rotor blades cannot adjust quickly enough to prevent speed from exceeding the nominal value, especially during transitions from calm to gusty conditions.
Innovation Solution
Defining a limit angle as the minimum blade angle and allowing it to be undercut by a predetermined differential angle, which varies based on gust frequency and detected peak speeds, to prevent excessive blade angle deviation and ensure smooth adjustments during wind fluctuations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the overspeed limit is set only slightly above the rated speed for safety reasons, then the wind turbine is protected from dangerous overspeed conditions, but the control system may trigger emergency shutdown even when it cannot turn the rotor blades out of the wind quickly enough due to gusty winds with short periods of very weak wind
Solution Approach 1:
The patent applies dynamics by making the overspeed limit time-varying rather than fixed. During gusty wind conditions with short periods of very weak wind, the overspeed limit is temporarily increased above the normal safety threshold. This dynamic adjustment allows the control system to distinguish between dangerous overspeed conditions requiring shutdown and temporary exceedances caused by wind gusts, thereby preventing unnecessary emergency shutdowns while maintaining protection against truly dangerous conditions.
Solution Approach 2:
The patent changes the parameter of the overspeed limit based on detected wind conditions. When gusty winds are detected (characterized by short periods of very weak wind between gusts), the overspeed limit parameter is adjusted upward. This parameter change enables the system to accommodate temporary blade positioning limitations during gusty conditions without triggering false emergency shutdowns, while maintaining strict limits during normal operating conditions.
2Stability of the object's composition
If the rotor blades are turned further out of the wind as the wind increases to maintain constant rotational speed, then the rotational speed remains stable at rated speed, but during gusty winds with temporary lulls, the blades cannot be turned back quickly enough when gusts return, causing overspeed
Solution Approach 1:
The patent applies dynamics by implementing a time-varying overspeed limit that adapts to gusty wind conditions. When gusty winds with temporary lulls are detected, the overspeed limit is temporarily raised, allowing the rotational speed to exceed the normal rated speed without triggering emergency shutdown. This dynamic threshold accommodates the physical limitation of blade response time during gusty conditions while maintaining stability during normal operation.
Data Source
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AI summary
The invention relates to a method for controlling a wind turbine with rotor blades having an adjustable blade angle (α), comprising the steps of: operating the wind turbine in a part-load operation for wind speeds up to a rated wind speed; operating the wind turbine in a full-load operation for wind speeds above the rated wind speed, the blade angle (α) being widened as the wind speed increases during the full-load operation; determining a critical angle (αG) as the minimum value of the blade angle (α); and controlling the wind turbine such that the critical angle (αG) is only fallen short of, at the most, by a predetermined differential angle (Δα).