Effect of pitching motion on production in a OFWT

The performance of offshore floating wind turbines (OFWTs) is affected by the movement along the 6 Degrees of Freedom (DOFs), which is caused by the combined influence of wind and waves. Particularly, interesting is the pitching motion, which can lead to significant changes in aerodynamic and net generated power. This paper analyzes the influence of pitching motion on the net generated power, considering for the first time in literature the OFWT control systems (blade pitch and generator controller). An in-house model based on the Blade Element Momentum (BEM) theory is used, in which sinusoidal pitch movements characterized by different values of amplitude, frequency and offset are imposed. In this way, it is possible to evaluate the influence of these three parameters on the extracted power at different values of wind speed. Results identify in the pitch amplitude and frequency the most significant variables for variations in OFWT power output, and that the influence of pitch oscillation on the average extracted power considerably varies at different wind conditions.