Quasi-Z-source-based bidirectional DC-DC converters for renewable energy applications

This article presents a design, analysis, and implementation of a novel impedance-source-based bidirectional DC-DC converter. The proposed converter employs an impedance network to the existing dual-active-bridge (DAB) circuit. It inherits all the advantages of the DAB converter along with extra benefits. Compared with the traditional isolated DC-DC converter, the proposed converter improved the boost ability of the converter. Also, the converter can withstand the shoot-through phenomenon in an H-bridge, improving the reliability. The converter can work in the normal buck/boost DAB mode when extra boost is not required. The bidirectional feature is inherent along with soft switching capability. It is therefore well-suited for the applications, where wide range of voltage gains are required such as renewable energy systems. The topological configuration and control strategy of the proposed topology in both operational modes are discussed. Simulation and experiments have been carried out to demonstrate the effectiveness of the proposed converter topology. The peak efficiency 97% was observed at the rated load of 500 W.