Dynamic modeling and load calculation method based on offshore semi-submersible fan

The invention discloses a dynamic modeling and load calculation method for an offshore semi-submersible wind turbine, which is characterized in that when the semi-submersible wind turbine stably operates in deep sea, the semi-submersible wind turbine is subjected to the action of wind wave load, a semi-submersible platform is subjected to the tension of an anchor chain, and the wind turbine is also provided with a variable-pitch control system; in order to research the load change condition of the semi-submersible fan in the variable pitch process, firstly, a kinetic equation of the semi-submersible fan is established, damping and rigidity coefficients are considered, the damping of the semi-submersible fan is expressed as a nonlinear mode due to the fact that the damping of a floating fan is too complex, and the rigidity coefficient of the semi-submersible fan is considered; and identifying the rigidity and the damping coefficient of the semi-submersible fan by using a system identification method, namely an