Responses Of Motion And Power Of The Floating Multi-body Wave Energy Converter With Different Shapes

Wave energy is considered as one of the most promising renewable energy sources.Compared with the point type,the line absorbing wave power generation device has a greater advantage in the large scale power generation because of its higher wave energy capture efficiency and greater stand-alone power.Study on the hydrodynamic characteristics of floating bodies in a double raft type wave power generation device is conducted in this paper,focusing on the linear wave conditions,through numerically analyzing the impacts of floating body geometry(cuboid,cylinder,elliptic cylinder or capsule)on the floating body wave motion and energy.Base on the linear wave theory,the control coupled equation of the heaving-pitching motion for the WEC is deduced considering with the constraint of PTO(Power Take-off)damping and return spring.And the motion constraint equation is introduced to realize the coupling of theory motion equations of the WEC.Based on the phase difference law and the resonance mechanism of buoys,the optimization scheme of the buoy is put forward by using the frequency domain method.Study the effect relationship to the characteristics of buoys relative pitching motion of wave period,wave height and draft.Base on three sections of floating body,considering the environmental load and the hydraulic cylinder damping by numerical simulation analysis of the variations of the shape of the floating body pitch angle,and derived formula of WEC capture power,study on the effect of wave period,wave height,draught power on energy harvesting device parameters,and compare the wave resistance of the shape of the buoys.The numerical results show that in typical period,Each shape device power is increased first and then decreased,the capsule body has the greatest power,with the increase of wave height,the capsule body power increase speed more than others,the cylinder has the best wave resistance.