Simple model for describing and estimating wind turbine dynamic inflow

Abstract

Abstract-Wind turbines operate with sudden change in pitch angle, rotor or wind speed. In such cases the wake behind the turbine, achieve steady state conditions only after a certain delay. This phenomenon is commonly called dynamic inflow.There are many models for dynamic inflow. The most accurate use a method that can be characterised as the blade element momentum method plus a dynamic equation for the induction factor. This method then needs calculations along the blade for a number of sections including numerical solution of equations. This is numerical demanding. The simplest models amounts to placing a lead-lag filter after rotor torque and thrust calculated from static tables of the power and thrust coefficients. The filter constants will then vary with average wind speed. The filtered versions of torque and thrust are then an approximate modelling of the dynamic inflow. The dynamic inflow model suggested here places itself in between the most complex and the most simple both in accuracy, numerical demands and physical appeal. The suggested models behavior is demonstrated by simulation and the usefulness for extended Kalman filtering is assessed both via simulated data and real full scale turbine data.

Wave disturbance rejection for monopile offshore wind turbines

“…Moreover, if the dynamic wake effect is not accounted for, the aerodynamic damping is not represented correctly. Several control‐oriented models that aim to capture the dynamic wake effect, often referred to as dynamic inflow models, have been developed . Here, the single‐state dynamic inflow model proposed by Henriksen et al is used.…”

“…Several control-oriented models that aim to capture the dynamic wake effect, often referred to as dynamic inflow models, have been developed. 23,32,33 Here, the single-state dynamic inflow model proposed by…”

Health‐aware model predictive control of wind turbines using fatigue prognosis

“…The model include states representing the rotor speed, ω r , the tower fore-aft displacement, d t , the tower fore-aft velocity, the generator torque, T g , the pitch angle, β. In addition to these standard states, the first order dynamic inflow model from Knudsen and Bak [2013] is included. The controlled inputs are generator torque and pitch references, respectively T g,ref and β ref .…”

Model predictive control for wind power gradients

“…In other words, by blade pitch control, we can vary the extracted power from 0 up to the maximum available power. We disregard the effects of dynamic inflow of the wind during fast pitching events, described in, e.g., the works by Knudsen and Bak and Øye . In these papers, the transient time of the dynamic inflow is observed to be in the range of 8–20 s. Thus, with a sample rate of 10 s, such effects are not relevant to this study.…”

“…We disregard the effects of dynamic inflow of the wind during fast pitching events, described in, e.g., the works by Knudsen and Bak and Øye. [52][53][54] In these papers, the transient time of the dynamic inflow is observed to be in the range of 8-20 s. Thus, with a sample rate of 10 s, such effects are not relevant to this study. We define the function ‰ .v, K, P w / as the value ofˇthat gives the extracted power P w .…”