Design And Hydrodynamic Performance Analysis Of Offshore Floating Photovoltaic Device

Floating photovoltaic(PV)on the sea is a new type of marine structure that needs to adapt to harsh marine environments by relying on its own structure during operation.The hydrodynamic performance is an important factor affecting the operational safety of floating PV on the sea.It is not only influenced by loads such as wind,waves,and currents,but also requires consideration of the coupling effect between multiple module floaters and mooring systems,which has a complex expression and significant research value.This article proposes a design scheme for a triangular-shaped floating PV on the sea,and based on this,three total layout design schemes for multiple module combinations are proposed.Flexible connection schemes and semi-taut mooring schemes are designed for the three total layout schemes,and hydrodynamic performance analysis is conducted on the floating PV under the three total layout schemes in a sea area in Zhejiang Province,China.This provides a reference for the practical application of the floating PV on the sea,and the main research contents are as follows:(1)A single-module floating PV design scheme with a triangular-shaped main body structure is proposed,and the floating and PV systems of the floating PV are designed in detail.Based on the single-module floating PV as the basic module unit,three total layout design schemes are proposed for single-module,double-module,and six-module combinations,with PV installation capacities of 0.25 MW,0.50 MW,and 1.50 MW,respectively.In the double-module and six-module total layout schemes,a flexible connection design scheme is used between the two modules.A semi-taut mooring scheme is designed for the mooring requirements of the floating PV in the three total layout schemes,and a design example of the floating PV under the three total layout schemes is given based on the sea conditions in a sea area in Zhejiang Province.(2)The floating PV frequency domain analysis method is established based on the threedimensional potential flow theory to calculate the hydrodynamic performance of the floating PV under the three design examples in the frequency domain.According to the frequency domain analysis method,the additional mass,radiation damping,first-order wave excitation force,steady drift force,and motion response amplitude operator of the selected module of the floating PV under different wave directions are calculated for the three design examples.The results show that the frequency domain hydrodynamic response of the floating PV under the three layouts is basically the same,but the first-order wave excitation force and motion response amplitude operator of the floating PV under 90° transverse waves exhibit significant frequency response in the pitch direction.(3)The time domain analysis method for multiple module floating PV is established based on the frequency domain calculation results,considering the effects of environmental loads such as wind,waves,and currents.The floating PV,mooring system,and connection structure under the three total layout schemes are subjected to coupled analysis to calculate the time domain motion response,mooring tension,and connection structure force of the floating PV under 90° transverse waves.The results show that the hydrodynamic response of the floating PV is the smallest under the six-module layout,followed by the single-module layout,and the largest under the double-module layout.(4)Taking the double-module layout floating PV as an example,the hydrodynamic performance of the floating PV under different wave directions and wave periods is studied.The calculation results show that compared with other wave directions,the motion response of the floating PV under the 0° head-on wave is relatively stable,and the overall force on each connection structure is smaller,indicating better hydrodynamic performance.Under different wave periods,the force on each connection structure of the floating PV is relatively smaller under the long-period condition,which is more conducive to the operation of the floating PV.