Determination of oscillation frequencies of wind turbines and related methods
The present disclosure is related to methods for determining a frequency of an oscillation mode of a wind turbine, comprising: determining a motion of a first mass of a first tuned mass damper in the wind turbine and deriving the frequency of the oscillation mode of the wind turbine at least partially based on the determined motion of the first mass. The present disclosure further relates to methods for operating a wind turbine, and to wind turbines, particularly offshore wind turbines, comprising tuned mass dampers.
1 . A method for determining an updated frequency of an oscillation mode of a wind turbine, the method comprising:
during a power-production or idling mode of the wind turbine, determining a frequency of oscillation motion of a first mass of a first tuned mass damper in the wind turbine;
deriving the updated frequency of the oscillation mode of the wind turbine in the power-production or idling mode at least partially based on changes to the frequency of oscillation motion of the first mass; and
in a control system of the wind turbine, incorporating the updated frequency of the oscillation mode of the wind turbine into one or more control strategies so that the one or more control strategies are adjusted based on the updated frequency of the oscillation mode of the wind turbine.
2 . The method of claim 1 , wherein the oscillation mode of the wind turbine is a first normal mode.
3 . The method of claim 1 , further comprising determining a frequency of oscillation motion of a second mass of a second tuned mass damper in the wind turbine, and deriving the frequency of the oscillation mode of the wind turbine also based at least partially based on the frequency of oscillation motion of the second mass.
4 . The method of claim 3 , wherein the first mass and the second mass are configured to move in substantially perpendicular directions relative to each other.
5 . The method of claim 1 , wherein determining the frequency of oscillation motion of the first mass of the first tuned mass damper comprises deriving a speed of motion of the first mass by monitoring a position of the first mass with respect to the wind turbine as a function of time.
6 . The method of claim 5 , wherein monitoring the position of the first mass comprises detecting the first mass at a target location.
7 . The method of claim 1 , wherein adjusting the control strategy comprises changing a pitch control strategy to avoid resonance in the wind turbine.
8 . A method for operating a wind turbine, the method comprising;
determining an updated frequency of an oscillation mode of the wind turbine during a power-production or idling mode of the wind turbine by:
determining a frequency of oscillation motion of a first mass of a first tuned mass damper in the wind turbine; and
deriving the updated frequency of the oscillation mode of the wind turbine in the power-production or idling mode at least partially based on the frequency of oscillation motion of the first mass;
the method further comprising:
changing an exclusion range of rotational speeds of a rotor of the wind turbine so as to be based on the updated frequency of the oscillation mode; and
operating the wind turbine so that an operational time of the wind turbine in the exclusion range is reduced or avoided due to changing the exclusion range to be based on the updated frequency of the oscillation mode.
9 . The method of claim 8 , further comprising determining a new frequency of the oscillation mode based on the frequency of oscillation motion of the first mass after a period of operation of the wind turbine and adjusting the exclusion range based on the new frequency.
10 . The method of claim 9 , further comprising adjusting the first tuned mass damper based on the new frequency.
11 . The method of claim 9 , further comprising storing historical data relative to the frequency of the oscillation mode; and estimating a remaining life expectancy of the wind turbine at least partially based on the stored historical data.
12 . A wind turbine, comprising:
a tuned mass damper having a first mass;
a control system in communication with the tuned mass damper, the control system configured to carry out the method according to claim 1 .