An Interleaved High-Power Fly back Inverter for Photovoltaic Applications

Abstract

This paper presents analysis, design, and implementation of an isolated grid-connected inverter for photovoltaic
(PV) applications based on interleaved fly back converter topology operating in discontinuous current mode. In
today’s PV inverter technology, the simple and the low-cost advantage of the fly back topology is promoted only at
very low power as micro inverter .Therefore, the primary objective of this study is to design the fly back 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 fly back 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.