Vibration Control of Wind Turbine Towers With Kdamper-Based Designs

Abstract

The application of dynamic vibration absorbers (DVA) to Wind Turbine (WT) towers has the potential to significantly improve the damping of the tower and the nacelle dynamic responses, thus increasing the reliability of WTs. The Tuned Mass Damper (TMD) is considered a benchmark for vibration absorption of WT. However, its effectiveness is limited by the requirement of large masses, in association to its installation location. Thus, an alternative concept is introduced, which is based on a novel passive vibration absorption configuration, the extended KDamper concept. The KDamper is essentially an extension of the conventional TMD, introducing appropriate negative stiffness (NS) elements. Instead of increasing the additional mass, the vibration absorption capability of the KDamper can be increased by increasing the value of the NS element. Therefore, the KDamper always indicates better isolation properties than a TMD with the same additional mass. In this paper, the performance of these concepts is examined for increasing the damping of WT towers. A constrained optimization procedure is presented, from which the optimal design parameters are obtained. Although both concepts present a good behavior, the KDamper-based design significantly increases the effective damping of the WT tower, retaining the additional masses in reasonable ranges.