Novel output filter of flyback inverter for photovoltaic AC-module

In the photovoltaic (PV) AC-module system, the system size and weight are important design factors because AC-modules are installed to each PV panels. Since the most of harmonics occur at multiples of switching frequency, the harmonic elimination at switching frequency can be an effective technique for reducing the total filter size. To decrease output filter size, proposed output filter consists of trap filter to eliminate switching frequency harmonic and CL filter. In this paper, the trap-CL filter is analyzed, and its optimal design method is proposed. The validity of proposed filter and design method are verified by simulation and experimental results.