A Modified Series-Capacitor High Conversion Ratio DC–DC Converter Eliminating Start-Up Voltage Stress Problem

In this letter, a modified series-capacitor (SC) high conversion ratio (HCR) dc-dc converter is proposed. The proposed converter inherits most of the advantages of the existing SC HCR dc-dc converter and can eliminate the problem of high switch-voltage stress of the existing converter encountered during start-up using a simple circuit modification. Although an extra capacitor is required in the proposed converter, total series capacitance of the proposed converter is the same as that of the conventional SC converter. In addition, input capacitance of the proposed converter can be reduced by less than half of that of the SC buck converter. A 1-kW prototype converter is built and tested to verify the performance of the proposed converter.