High Step-down Converters for Battery Charging in Photovoltaic Applications

This paper describes non-isolated high step-down converters used to connect photovoltaic modules to the battery storage of a bicycle charging station. Due to the high voltage difference between input and output, some problems may occur with conventional non-isolated DC-DC buck converters. The characteristics of alternative topologies of high step-down converters have been explored. Ideal converter models were created in the PLECS simulation software package based on which the voltage and current stress of the semiconductor switches were determined. Based on measured voltage and current relations, commercial switches were selected. Based on catalogue data, electro-thermal models of the switches were created. A comparative analysis of converters based on conduction and switching losses was performed. Converters were also compared based on the number of components and complexity of control.