Comparative analysis of 1DOF vs. 2DOF speed increasers for counter-rotating wind turbines

The paper presents a comparative study on the cinematic and static performance of a new type of planetary speed increaser for wind turbines. In this respect, the analytical modeling of the mechanical response for a counter-rotation wind system consisting of two identical counter-rotating wind turbines, an electric generator with fixed stator and a two-inputs one-output planetary speed increaser which can operate in two distinct situations: as a differential (2DOF) increaser (summing the input speeds) or as a monomobile (1DOF) increaser (summing the input moments) is obtained in the first part. For a numerical case study, the mechanical response of the wind system is simulated in the two stated functional situations, considering 1DOF vs. 2DOF speed increasers. The obtained results show a better energetic behavior of the 1DOF wind system as a result of a higher efficiency, but with a higher degree of load unevenness of the two wind turbines.