Abstract. The current trend toward larger wind turbine rotors leads to high periodic loads across the components due to the non-uniformity of inflow across the rotor. On this regard, we introduce a blade-mounted lidar on each blade to provide a preview of inflow wind speed that can be used as a feedforward control input for the mitigation of such periodic blade loads. We present a method to easily determine blade-mounted lidar parameters, such as focus distance, telescope position, and orientation on the blade. However, such method is accompanied by uncertainties in the inflow wind speed measurement, which may also be due to the induction zone, wind evolution, cyclops dilemma, unidentified misalignment in the telescope orientation, and the blade segment orientation sensor. Identification of these uncertainties allows their inclusion in the feedback-feedforward controller development for load mitigation. We perform large-eddy simulations, in which we simulate the blade-mounted lidar including the dynamic behaviour and the induction zone of one reference wind turbine for one above rated inflow wind speed. Our calculation approach provides a good trade-off between a fast-and-simple determination of the telescope parameters and an accurate inflow wind speed measurement. We identify and model the uncertainties, which then can directly be included in the feedback-feedforward controller design and analysis. The rotor induction effect increases the preview time, which needs to be considered in the controller development and implementation.
Wind speed measurement for absolute power curve determination from induction zone lidar measurements
