Objective Floating photovoltaic power generation platforms have been widely used in marine resource development due to their advantages of land resource conservation and efficient power generation. However, current floating PV structures are mainly composed of metal frames and buoyancy materials, which are prone to structural damage when facing complex natural conditions. To avoid instability of floating PV power generation systems on the sea surface, it is necessary to study the hydrodynamic characteristics of the PV system under different wind, wave and current conditions.

Method This paper adopted physical model testing methods. Based on the actual PV power generation system, a 4×5 floating PV model was designed. The QUALISYS motion capture system was used to record the motion data of the PV modules. Free decay experiments and motion response experiments were conducted on the floating PV modules, while monitoring the air gap between the PV deck and the water surface. The hydrodynamic characteristics of the floating PV modules under different sea states were analyzed through experimental results.

Result The results of the free decay experiment show that the roll natural period of the floating PV monomer module is 1.35 s, the pitch natural period is 1.33 s, and the heave natural period is 1.55 s. The results of the motion response experiment show that when the water depth is 0.495 m, the water force will cause displacement of the system. The results of the air gap experiment show that under extreme loads, the minimum average value of the air gap of the floating PV system is 105 mm.

Conclusion The free decay experiment indicates that the floating PV system exhibits approximately isotropic dynamic characteristics in the horizontal plane. The results of the motion response experiment show that the photovoltaic floating mooring system is greatly affected by current, and parametric resonance occurs between the PV modules, resulting in significant motion response perpendicular to the wave incidence direction. Under pure current conditions, due to the complex flow effects between the fluid and each module, the motion responses of each module in both the incident direction and the vertical direction along the sea current cannot be ignored. Under the designed test conditions, the air gap of the modules did not appear negative, and no wave impact on the PV deck occurred during the experiment.