Calculation and characteristics analysis of blade pitch loads for large scale wind turbines

Based on the electric pitch system of large scale horizontal-axis wind turbines, the blade pitch loads coming mainly from centrifugal force, aerodynamic force and gravity are analyzed, and the calculation models for them are established in this paper. For illustration, a 1.2 MW wind turbine is introduced as a practical sample, and its blade pitch loads from centrifugal force, aerodynamic force and gravity are calculated and analyzed separately and synthetically. The research results showed that in the process of rotor rotating 360 degrees, the fluctuation of blade pitch loads is similar to cosine curve when the rotor rotational speed, inflow wind speed and pitch angle are constant. Furthermore, the amplitude of blade pitch load presents quite a difference at a different pitch angle. The ways of calculation for blade pitch loads are of the universality, and are helpful for further research of the individual pitch control system.