Improving the Efficiency of Floating Photovoltaic System in the Northern Part of Iran Using a Two-stage Multi-String Inverter

Floating photovoltaic (FPV) systems are a new approach to the use of water-based photovoltaic (PV) systems. This system creates a new opportunity to increase the production capacity of solar PV systems, especially in the northern regions of Iran, where the price of land is high. To enhance the efficiency of inverters connected to the network of FPV systems in the northern regions of Iran, we have combined the structure of a two-stage and a multi-string inverter in this paper. On the other hand, the perturb and observe (P&O) method is one of the most common methods for maximum power point tracking (MPPT) with a variety of disadvantages including algorithm fluctuations during sudden changes in radiation. Since these sudden changes during radiation occur abundantly in the northern regions of Iran due to cloudy weather, a modified P&O algorithm is proposed by adding a current change parameter to overcome this problem. In fact, the ZETA converter and the proposed algorithm are used in inverter and track the maximum power point and in the second stage, DC to AC conversion occurs. To evaluate the efficiency improvement, the proposed inverter is compared with a single-stage centralized inverter. This study also considered the effect of wind and water temperature on the production capacity of the FPV system. System simulation is performed using Matlab/Simulink software. The simulation results show that the proposed two-stage multi-string inverter produce an average of 18.88 kWh, which is an increase compared to the centralized single-stage inverter.