Pole-Placement-Based Calibration of an Electromagnetically Realizable Inerter-Based Vibration Absorber (IDVA) for Rotating Wind Turbine Blades

This paper deals with edgewise vibration mitigation of rotating wind turbine blades by means of inerter-based vibration absorber (IDVA), which can be realized both mechanically and electromagnetically. Introducing the electromagnetically-realizable IDVA to the blade forms a 3-degree-of-freedom (3-DOF) blade-IDVA system consisting of the rotating blade, an absorber, and a series inerter-dashpot-spring subsystem. Analytical optimal design formulas of the rotating blade-installed IDVA are then derived using a pole-placement method where the equal-modal-damping-ratio principle and the triple-root-bifurcation condition are applied. The analytical formulas show that the optimal parameters for the blade-IDVA system merely depend on the spinning speed of the rotor given the IDVA location and the absorber mass. Numerical results of the NREL 5 MW wind turbine with optimal IDVA show that optimal IDVA leads to superior performance than optimal TMD in mitigating the blade edgewise vibration and behaves nearly as same as optimal RIDTMD, along with slightly optimal damper parameters variation. This means that the inerter-dashpot-spring system can be deployed flexibly for damping edgewise vibrations of rotating blades.