A DC–DC Converter With Quadratic Gain and Bidirectional Capability for Batteries/Supercapacitors

Energy storage devices are essential to provide voltage and frequency stability in renewable energy sources, such as solar and wind. Due to operational requirements of distributed generation systems, energy storage devices like batteries and supercapacitors need bidirectional dc-dc converters to allow charge or discharge exchange according with the necessary conditions. In this paper, a new nonisolated bidirectional quadratic converter characterized by high voltage gain in both step-down (Buck) and step-up (Boost) operation modes is proposed. In addition to the wide conversion range, it presents continuous input and output current and reduced charging/discharging ripple. All these features allow an optimized operation between the dc bus and storage devices. The operation principle of the proposed converter in both condition modes (step-down and step-up), the converter design, as well as the theoretical analysis in different conditions will be discussed. Finally, the performance of the proposed converter is confirmed through simulation and experimental results.