A Common-Ground Bidirectional Hybrid Switched-Capacitor DC–DC Converter with a High Voltage Conversion Ratio

Abstract

Electrical energy conversion and storage in DC systems, with increasing importance in industry, requires DC–DC power electronic converters with performances adapted to today’s requirements. In recent years, the applications of DC–DC converters have expanded, including energy storage management strategies, due to the use of supercapacitors for energy storage instead of—or together with—rechargeable batteries, in order to improve overall performance. This article presents a non-isolated, common-ground, bidirectional hybrid switched-capacitor DC–DC converter, which can be efficiently used for supercapacitor charging/discharging, due to its high voltage conversion ratio. The hybrid converter was obtained from the conventional bidirectional buck topology, inserting an “active” switched-capacitor cell. In addition to the high voltage conversion ratio, the switched-capacitor cell brings another important advantage: decreasing the values of all passive components without interrupting the input to the output ground path. All of these positive features were revealed through theoretical analysis and confirmed through digital simulations and experiments, proving that the hybrid converter performs well in both operating modes, with a smooth transition between them.