Development of sea wind turbine system structure analysis method by using multi-body dynamics

Dynamics analysis of a floating wind turbine system is coupled with aero-elastic dynamics, hydro dynamics, multibody dynamics and control system. The aero-elastic dynamics code has been developed by NREL(National Renewable Energy Laboratory, USA). The hydro dynamics code has been developed by KIMM(Korea Institute of Machinery & Materials) and SNU(Seoul National University). Those codes have been merged on the commercial multi-body dynamics software of DAFUL made in VM(Virtual Motion). A wind turbine system consists of blade, hub, power train, nacelle, tower, platform, mooring. The blade and tower are modeled as multi-body system to apply an aero force and elastic force. Pitch and generator torque are controlled with PID controller. Added mass, damping, restoring, mooring and buoyancy forces are applied on the platform. This analysis method is verified by NREL OC3 model and FAST, developed in NREL. As a result, the two results agree well enough to verify the reliability