An Interleaved High-Power Flyback Inverter for Photovoltaic Applications

This paper presents analysis, design, and implementation of an isolated grid-connected inverter for photovoltaic (PV) applications based on interleaved flyback converter topology operating in discontinuous current mode. In today´s PV inverter technology, the simple and the low-cost advantage of the flyback topology is promoted only at very low power as microinverter. Therefore, the primary objective of this study is to design the flyback converter at high power and demonstrate its practicality with good performance as a central-type PV inverter. For this purpose, an inverter system rated at 2 kW is developed by interleaving of only three flyback cells with added benefit of reduced size of passive filtering elements. A simulation model is developed in the piecewise linear electrical circuit simulator. Then, the design is verified and optimized for the best performance based on the simulation results. Finally, a prototype at rated power is built and evaluated under the realistic conditions. The efficiency of the inverter, the total harmonic distortion of the grid current, and the power factor are measured as 90.16%, 4.42%, and 0.998, respectively. Consequently, it is demonstrated that the performance of the proposed system is comparable to the commercial isolated PV inverters in the market, but it may have some cost advantage.