Study on Controller Tuning of Wind Turbines with Backward Swept Blades

Abstract

The objective of this study is to investigate the effects of backward swept blades on the dynamics of the controller of a wind turbine. When sweeping blades backward a coupling between flapwise bending toward the tower and torsion towards feathering is achieved. This coupling mitigates loads on the structure due to a decrease in the angle of attack. Changing the blade geometry can affect the behavior of the wind turbine controller. Hence, a detailed investigation of the effects generated by the blade sweep on the controller tuning is needed. Using the Basic DTU Wind Energy Controller, the aero-servo-elastic behavior of the 10 MW DTU Reference Wind Turbine (RWT) with swept blades is studied and considerations on the tuning of the controller are made in order to preserve and not compromise the dynamics of the system. This work focuses on understanding the interaction between the employment of backward swept blades and the dynamic behavior of the controller above rated wind speed. The purpose is to isolate loads variations due to the blade sweep from the loading differences brought by the controller’s actions. This objective is achieved by re-tuning the controller of the wind turbine with swept blades according to the dynamics of the baseline regulator mode.