Bidirectional DC-DC soft-switching converter for stand-alone photovoltaic power generation systems

In this study, the authors focused on developing a bidirectional power converter for a stand-alone photovoltaic power generation system when a lithium-ion battery is used to regulate the power supply. Also, a small-scale air-conditioner was provided as the load for the bidirectional power converter developed to examine the efficiency of the converter. The overall framework of the proposed system comprised a maximum power point tracking controller, bidirectional buck-boost soft-switching converter, lithium-ion battery and small-scale air-conditioner. By attaching a resonant branch to a general bidirectional buck-boost converter and applying a simple switching signal control, soft switching was achieved, thereby increasing the power conversion efficiency of the photovoltaic power generation system. Some measurement results are made to verify the feasibility of the developed bidirectional dc-dc soft-switching converter for stand-alone photovoltaic power generation systems.