Study of a Cascaded Buck and Boost Converter for the Photovoltaic Power Generation System

In order to meet the needs of PV array output voltage in the wider range of PV generation system,the conventional Buck converter is combined with Boost converter in this paper.The combination means of converter is adopted to study a double-switch cascaded Buck and Boost.With an aim at the complicated disadvantages of the conventional Buck-Boost converter control and based on the input and output voltage conditions of the converter,three types of operation modes are suggested: i.e.Boost-voltage mode,Buck-voltage mode and critical operation mode.The operation principle of the converter and its control strategy are analyzed.Compared with the conventional Buck-Boost converter,its output voltage is positive and the input voltage ranges are wider.The simulation and experiment results prove that the cascaded Buck and Boost converter has good performance.