Horizontal axis wind turbines (HAWTs) are designed for a 20-year or longer activity, hence it is of great interest for the designers the assessment of loads acting on them in the different op- erational conditions. In this framework, unsteady aerodynamics effects produce vibratory loads which, in turn, may induce fatigue problems, but also affect the quality of power generated by the wind turbine (potentially causing problems to the electric grid) and increases noise generation. In principle, HAWT unsteady aerodynamics is related to non-axial wind orientation, but also the tower shadow effect may provide a not-negligible contribution. Indeed, each time a blade passes the tower, the blade airflow is perturbed, and this shadow effect is bigger on downwind turbines than on upwind turbines. Several strategies have been proposed in the past to mitigate fluctuations of aerodynamic loads and power output. In many cases, the pitch of the blades is controlled col- lectively, but this kind of control is not suited when non axi-symmetric loads are present and play a crucial role. In this work, first, a widely-applied tower shadow model is included in a nonlinear 9-dof HAWT aeroelastic model, and then, an original Multi Harmonics Individual blade Control suitable to alleviate the vibratory loads, while tracking the nominal angular velocity, is presented. The proposed control acts in such way that, once a specific undesired frequency acts on the sys- tem, the controller is capable to reject it by minimizing the error between the desired operating condition and the current one. The developed controller is applied on a 5MW HAWT.

Fratini, R., Serafini, J., Gennaretti, M., Santini, R., Panzieri, S. (2018). Reduction of Periodic Loads on Horizontal Axis Wind Turbines by Multi Harmonics Individual Blade Control. In 25th Congress on Sound and Vibration (ICSV25).

Reduction of Periodic Loads on Horizontal Axis Wind Turbines by Multi Harmonics Individual Blade Control

Riccardo Fratini;Jacopo Serafini;Massimo Gennaretti;Riccardo Santini;Stefano Panzieri
2018-01-01

Abstract

Horizontal axis wind turbines (HAWTs) are designed for a 20-year or longer activity, hence it is of great interest for the designers the assessment of loads acting on them in the different op- erational conditions. In this framework, unsteady aerodynamics effects produce vibratory loads which, in turn, may induce fatigue problems, but also affect the quality of power generated by the wind turbine (potentially causing problems to the electric grid) and increases noise generation. In principle, HAWT unsteady aerodynamics is related to non-axial wind orientation, but also the tower shadow effect may provide a not-negligible contribution. Indeed, each time a blade passes the tower, the blade airflow is perturbed, and this shadow effect is bigger on downwind turbines than on upwind turbines. Several strategies have been proposed in the past to mitigate fluctuations of aerodynamic loads and power output. In many cases, the pitch of the blades is controlled col- lectively, but this kind of control is not suited when non axi-symmetric loads are present and play a crucial role. In this work, first, a widely-applied tower shadow model is included in a nonlinear 9-dof HAWT aeroelastic model, and then, an original Multi Harmonics Individual blade Control suitable to alleviate the vibratory loads, while tracking the nominal angular velocity, is presented. The proposed control acts in such way that, once a specific undesired frequency acts on the sys- tem, the controller is capable to reject it by minimizing the error between the desired operating condition and the current one. The developed controller is applied on a 5MW HAWT.
2018
Fratini, R., Serafini, J., Gennaretti, M., Santini, R., Panzieri, S. (2018). Reduction of Periodic Loads on Horizontal Axis Wind Turbines by Multi Harmonics Individual Blade Control. In 25th Congress on Sound and Vibration (ICSV25).
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11590/338119
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