European Wind Energy Conference and Exhibition 2006 Athens, Greece EWEC’06 Athens 27 February-2 March 20061/16 Investigation of the Stability Bounds of Wind Turbines in view of Passive Instability Suppression V.A.Riziotis and S.G.Voutsinas National Technical University of Athens School of Mechanical Engineering Fluids Section E.S. Politis and P. K. Chaviaropoulos Centre for Renewable Energy Sources Wind Energy Section
EWEC’06 Athens 27 February-2 March /16 NTUA Overview of the Presentation
EWEC’06 Athens 27 February-2 March /16 NTUA
EWEC’06 Athens 27 February-2 March /16 NTUA isolated blade analysis 2% improvement in power production 1 st lead-lag 1 st flap
EWEC’06 Athens 27 February-2 March /16 NTUA full wind turbine analysis
EWEC’06 Athens 27 February-2 March /16 NTUA ReferenceModified 1Modified 2 Freq(hz) red(%)Freq(hz)red(%) 1st flap st lag nd flap
EWEC’06 Athens 27 February-2 March /16 NTUA 1 st flap 2 nd cyclic flap 1 st cyclic lead-lag
EWEC’06 Athens 27 February-2 March /16 NTUA 1 st flap 2 nd cyclic flap 1 st cyclic lead-lag
EWEC’06 Athens 27 February-2 March /16 NTUA 1 st flap 2 nd cyclic flap 1 st cyclic lead-lag Reference modified 2 regressive lead-lag mode shape
EWEC’06 Athens 27 February-2 March /16 NTUA isolated blade analysis FOIL2W: 2D viscous-inviscid interaction model wind speed 12m/s 1 st lead-lag mode
EWEC’06 Athens 27 February-2 March /16 NTUA introduction of a soft connection of the nacelle with the tower k yaw = 5x10 5 Nm/rad
EWEC’06 Athens 27 February-2 March /16 NTUA Effect from the introduction of a soft yaw connection on the damping of the rotor lead- lag modes Application to a Pitch-Variable Speed wind turbine
EWEC’06 Athens 27 February-2 March /16 NTUA 2 nd flap 1 st lag Reference soft yaw regressive lead-lag mode shape
EWEC’06 Athens 27 February-2 March /16 NTUA Effect from the introduction of a soft yaw connection on the damping of the rotor lead- lag modes Application to an Active Stall wind turbine
EWEC’06 Athens 27 February-2 March /16 NTUA Conclusions
EWEC’06 Athens 27 February-2 March /16 NTUA Acknowledgements European Commission & Greek Secretariat for Research and Technology for co-funding this work under contract NNK5-CT (STABCON project) STABCON project partners for publishing of the paper