Method of determining the vertical profile of the wind speed upstream from a wind turbine equipped with a lidar sensor
AssigneeIfp Energies Nouvelles
InventorsHoai-Nam Nguyen, Fabrice Guillemin
Life of this patent
Estimating the term…
Abstract
The invention relates to a method of determining the vertical profile of the wind speed upstream from a wind turbine (1), wherein wind speed measurements are performed by a LiDAR sensor (2), then the exponent α of the power law is determined by an unscented Kalman filter and measurements, and the exponent α is applied to the power law in order to determine the vertical wind speed profile.
Claims5
A method of determining a vertical profile of wind speed upstream from a wind turbine, the vertical profile of wind speed being a wind speed gradient as a function of altitude, the wind turbine being equipped with a rotor and a LiDAR sensor facing upstream from the wind turbine and controlling the wind turbine comprising:
- a) measuring the wind speed with the LIDAR sensor in at least one measurement plane of the rotor upstream from the wind turbine located at least at two measurement points at different heights;
- b) constructing a model of the vertical wind speed profile using a power law of a form:
- v
- z
- v
- z
- 0
- =
- (
- z
- z
- 0
- )
- α
- with vz being longitudinal wind speed at height z, z0 being a reference height, vz0 being a longitudinal wind speed at the reference height z0 and α being an exponent of the power law;
- c) determining the exponent α of the power law by use of an unscented Kalman filter by using wind speed measurements from the at least two measurement points, wherein the unscented Kalman filter being applied to a state model comprising additive noise and multiplicative noise, the state model being written as:
- {
- x
-
- (
- k
- )
- =
- x
-
- (
- k
- -
- 1
- )
- +
- η
-
- (
- k
- -
- 1
- )
- ,
- y
-
- (
- k
- )
- =
- (
- v
- 2
- (
- k
- )
- +
- ϵ
- 2
- (
- k
- )
- )
-
- (
- z
- 1
- z
- 2
- )
- x
-
- (
- k
- )
- -
- ϵ
- 1
- (
- k
- )
-
- with x(k)=α(k) defining a state variable at time k, y(k)=v1(k) being an output of the state model corresponding to wind speed measured at time k at measurement point 1, η(k−1) is variation of exponent α at time k−1, v2(k) is the wind speed measured at time k at measurement point 2, z1 is height of measurement at point 1, z2 is height of measurement and point 2, ε1(k) is noise of speed v1 at time k, and ε2(k) is noise of speed v2 at time k;
- d) determining the vertical wind speed profile upstream from the wind turbine by applying the determined exponent α to the model of the vertical wind speed profile to determine vertical wind speed variation upstream from the wind turbine in the at least one measurement plane of the rotor;
- and
- e) controlling the wind turbine as a function of the determined vertical wind speed profile upstream from the wind turbine.
Dependencies are inferred from the claim text.