LAUSR

Abstract This paper presented a method for measuring windturbine blade clearance based on a millimeter-wave radar sensor that operates at a frequency of 24 GHz. The values of the change in the distance between the tower and the blade during operation process were constantly measured through eight mm-wave radar sensors mounted on the surface of the tower. The measurement in the radar sensor installation coordinate system was converted to the value in the nacelle rotation coordinate system through coordinate transformation, and then the minimum clearance distance between the blade and the tower was estimated through the method of the least square curve regression fitting. Furthermore, a feedforward (FF) control method with variable blade angle was proposed to control the blade clearance distance. A case study was provided to prove its practicality. Experimental results from a 2.65 MW wind turbine prove that using the proposed control method, the blade clearance value increased from a minimum distance of 5.65 m before control to 7.43 m after control, an increase of 30%.