Influence of the blades and the shaft rigidity of a wind turbine on the stability of the system under voltage dips

2012 ◽  
Author(s):  
Kamel Jemli ◽  
Bilel Touaiti ◽  
Mohamed Jemli
Keyword(s):  
Wind Turbine ◽  
Voltage Dips ◽  
The Stability

scholarly journals Mutual inductance instability of the tip vortices behind a wind turbine

2014 ◽  
Vol 755 ◽  
pp. 705-731 ◽  
Author(s):  
Sasan Sarmast ◽  
Reza Dadfar ◽  
Robert F. Mikkelsen ◽  
Philipp Schlatter ◽  
Stefan Ivanell ◽  
...  
Keyword(s):  
Growth Rate ◽  
Wind Turbine ◽  
Numerical Study ◽  
Operating Conditions ◽  
Analytical Relationship ◽  
Dynamic Mode ◽  
Spatial Structures ◽  
Tip Vortices ◽  
Positive Growth ◽  
The Stability

AbstractTwo modal decomposition techniques are employed to analyse the stability of wind turbine wakes. A numerical study on a single wind turbine wake is carried out focusing on the instability onset of the trailing tip vortices shed from the turbine blades. The numerical model is based on large-eddy simulations (LES) of the Navier–Stokes equations using the actuator line (ACL) method to simulate the wake behind the Tjæreborg wind turbine. The wake is perturbed by low-amplitude excitation sources located in the neighbourhood of the tip spirals. The amplification of the waves travelling along the spiral triggers instabilities, leading to breakdown of the wake. Based on the grid configurations and the type of excitations, two basic flow cases, symmetric and asymmetric, are identified. In the symmetric setup, we impose a 120° symmetry condition in the dynamics of the flow and in the asymmetric setup we calculate the full 360° wake. Different cases are subsequently analysed using dynamic mode decomposition (DMD) and proper orthogonal decomposition (POD). The results reveal that the main instability mechanism is dispersive and that the modal growth in the symmetric setup arises only for some specific frequencies and spatial structures, e.g. two dominant groups of modes with positive growth (spatial structures) are identified, while breaking the symmetry reveals that almost all the modes have positive growth rate. In both setups, the most unstable modes have a non-dimensional spatial growth rate close to $\def \xmlpi #1{}\def \mathsfbi #1{\boldsymbol {\mathsf {#1}}}\let \le =\leqslant \let \leq =\leqslant \let \ge =\geqslant \let \geq =\geqslant \def \Pr {\mathit {Pr}}\def \Fr {\mathit {Fr}}\def \Rey {\mathit {Re}}\pi /2$ and they are characterized by an out-of-phase displacement of successive helix turns leading to local vortex pairing. The present results indicate that the asymmetric case is crucial to study, as the stability characteristics of the flow change significantly compared to the symmetric configurations. Based on the constant non-dimensional growth rate of disturbances, we derive a new analytical relationship between the length of the wake up to the turbulent breakdown and the operating conditions of a wind turbine.

The Equations of Motion of n-Bladed Propellers with Arbitrarily Positioned Hinges and Their Application to an Experimental One-Bladed Wind Turbine

1985 ◽  
Vol 199 (4) ◽  
pp. 237-244
Author(s):  
M Person
Keyword(s):  
Wind Turbine ◽  
Equations Of Motion ◽  
Stability Analyses ◽  
Start Up ◽  
Different Types ◽  
The Stability

The equations of motion of n-bladed propellers with arbitrarily positioned hinges are derived out of the equations of a one-bladed propeller, by superposition. Different types of propellers are compared for time variances at the equations. An unbalanced start-up and the stability analyses (Floquet) of an experimental one-bladed propeller illustrate the need to consider the interaction of the motions of nacelle or hub and blade.

Study of stabilty analysis of a grid connected Doubly fed induction generator based on wind energy Application

2016 ◽  
Vol 3 (2) ◽  
pp. 305 ◽  
Author(s):  
Ghulam sarwar Kaloi ◽  
Jie Wang ◽  
Mazhar H Baloch
Keyword(s):  
Wind Turbine ◽  
Operating Conditions ◽  
Induction Generator ◽  
Doubly Fed Induction Generator ◽  
Grid Connection ◽  
Wind Turbine System ◽  
Space Modeling ◽  
Point Of Common Coupling ◽  
Doubly Fed ◽  
The Stability

<p><em> </em><em>     </em>The present paper formulates the state space modeling of doubly fed induction generator (DFIG) based wind turbine system for the purpose of the stability analysis. The objective of this study is to discuss the various modes of operation of the DFIG system under different operating conditions such as voltage sags with reference to variable wind speed and grid connection. The proposed control methodology exploits the potential of the DFIG scheme to avoid that grid voltage unbalances compromise the machine operation, and to compensate voltage unbalances at the point of common coupling (PCC), preventing adverse effects on loads connected next to the PCC. This methodology uses the rotor side converter (RSC) to control the stator current injected through the machine and the GSC to control the stator voltage to minimize the electromagnetic torque oscillations. Extensive simulation results on a 2MW DFIG wind turbine system illustrate the enhanced system performance and verify the effectiveness of the controller.</p>

EWSE and Uncertainty and Disturbance Estimator Based Pitch Angle Control for Wind Turbine Systems Operating in Above-Rated Wind Speed Region

2019 ◽  
Vol 142 (3) ◽  
Author(s):  
Xuguo Jiao ◽  
Qinmin Yang ◽  
Bo Fan ◽  
Qi Chen ◽  
Yong Sun ◽  
...  
Keyword(s):  
Wind Speed ◽  
Wind Turbine ◽  
Pitch Angle ◽  
Support Vector ◽  
Control Scheme ◽  
High System ◽  
Uncertainty And Disturbance Estimator ◽  
Systematic Solution ◽  
The Stability ◽  
Disturbance Estimator

Abstract As wind energy becomes a larger part of the world's energy portfolio, the control of wind turbines is still confronted with challenges including wind speed randomness and high system uncertainties. In this study, a novel pitch angle controller based on effective wind speed estimation (EWSE) and uncertainty and disturbance estimator (UDE) is proposed for wind turbine systems (WTS) operating in above-rated wind speed region. The controller task is to maintain the WTS's generator power and rotor speed at their prescribed references, without measuring the wind speed information and accurate system model. This attempt also aims to bring a systematic solution to deal with different system characteristics over wide working range, including extreme and dynamic environmental conditions. First, support vector machine (SVR) based EWSE model is developed to estimate the effective wind speed in an online manner. Second, by integrating an UDE and EWSE model into the controller, highly turbulent and unpredictable dynamics introduced by wind speed and internal uncertainties is compensated. Rigid theoretical analysis guarantees the stability of the overall system. Finally, the performance of the novel pitch control scheme is testified via the professional Garrad Hassan (GH) bladed simulation platform with various working scenarios. The results reveal that the proposed approach achieves better performance in contrast to traditional L1 adaptive and proportional-integral (PI) pitch angle controllers.

Feasibility Study of the Floating Axis Wind Turbine: Preliminary Model Experiments

2017 ◽  
Author(s):  
Hiromichi Akimoto ◽  
Kazuhiro Iijima ◽  
Yasuhiro Takata
Keyword(s):  
Wind Turbine ◽  
Feasibility Study ◽  
Vertical Axis ◽  
Offshore Wind ◽  
Offshore Wind Turbine ◽  
Water Tank ◽  
Tank Model ◽  
Preliminary Model ◽  
Vertical Axis Turbine ◽  
The Stability

Floating Axis Wind Turbine is a concept of a floating vertical axis offshore wind turbine. In this design, a vertical axis turbine is directly mounted on a rotating spar buoy so that it does not require mechanical bearing supports of the heavy rotor. Multiple roller-generator units are on another small semi-sub float for extracting power from the rotating spar. A water tank model of 1/100 scale 5MW turbine and model power take-off units of about 1/20 scale are used for checking the concept. The results show the stability of the proposed turbine and demonstrates the function of roller-generator units.

Design of PSO Based PI Controller for Wind Turbine Systems

2013 ◽  
Vol 483 ◽  
pp. 529-532
Author(s):  
Jau Woei Perng ◽  
Guan Yan Chen ◽  
Der Min Tsay ◽  
Jao Hwa Kuang ◽  
Bor Jeng Lin ◽  
...  
Keyword(s):  
Wind Turbine ◽  
Operating Parameter ◽  
Pso Algorithm ◽  
Turbine Generator ◽  
Optimal Operating ◽  
Wind Turbine Generator ◽  
Artificial Learning ◽  
Control Stability ◽  
The Stability ◽  
Operating Points

This paper implements a strategy to obtain the proportional-integral (PI) optimal operating point and find the description of the stability regions in the parameters space. In order to do this, the particle swarm optimization (PSO) algorithm has been used in this study. The intelligent algorithm which is artificial learning mechanism could find optimal operating points and generates the function of the best operating parameter in the PI control stability region. Then the graphical method can provide boundaries of the PI type controller space for close-loop wind turbine generator (WTG) systems. The proposed techniques are presented by using simulation results to the WTG model.

scholarly journals Prediction of the hub vortex instability in a wind turbine wake: stability analysis with eddy-viscosity models calibrated on wind tunnel data

2014 ◽  
Vol 750 ◽  
Author(s):  
F. Viola ◽  
G. V. Iungo ◽  
S. Camarri ◽  
F. Porté-Agel ◽  
F. Gallaire
Keyword(s):  
Stability Analysis ◽  
Wind Tunnel ◽  
Wind Turbine ◽  
Eddy Viscosity ◽  
General Interest ◽  
Mean Velocity ◽  
Vortex Instability ◽  
Viscosity Models ◽  
Wind Tunnel Data ◽  
The Stability

AbstractThe instability of the hub vortex observed in wind turbine wakes has recently been studied by Iungo et al. (J. Fluid Mech., vol. 737, 2013, pp. 499–526) via local stability analysis of the mean velocity field measured through wind tunnel experiments. This analysis was carried out by neglecting the effect of turbulent fluctuations on the development of the coherent perturbations. In the present paper, we perform a stability analysis taking into account the Reynolds stresses modelled by eddy-viscosity models, which are calibrated on the wind tunnel data. This new formulation for the stability analysis leads to the identification of one clear dominant mode associated with the hub vortex instability, which is the one with the largest overall downstream amplification. Moreover, this analysis also predicts accurately the frequency of the hub vortex instability observed experimentally. The proposed formulation is of general interest for the stability analysis of swirling turbulent flows.

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