In order to use solar energy, which is converted to electricity by photovoltaic panels, various converters are employed for different applications. For instance, grid connected systems use high step up converters. Since photovoltaic panels have low voltage and power, they should be connected in parallel or series. On the other hand, due to problems associated with shading effect or mismatching between panels, the maximum achieved power may decrease and depends on the whole systems operation performance. Utilizing multi input converters instead of using several independent converters, is preferred due the system cost, size, and efficiency. Multi input converters are categorized into isolated and non isolated. In this thesis, after a survey of multi input converters and synthesis of high step up converters, a newly double input converter for grid connected photovoltaic power generation system is proposed. The purpose of this converter is to achieve maximum power from each input source. Also, one of the main features of this converter is that the inputs should transfer power to the output independently or simultaneously. In order to improve the performance of this converter, another topology is proposed. In this topology, an auxiliary circuit provides soft switching to reduce switching losses. Proposed converters are analyzed and the presented simulation results confirm their correct operation. Also these converters are implemented and the experimental results are presented Keywords : High step up converters, Multi input converters, Distributed MPPT, High step up converters in photovoltaic application.
