Quasi-Z-source inverter based bi-directional DC/DC converter: Analysis of experimental results

This paper presents simulation and experimental results of a quasi-Z-source inverter (qZSI) based bi-directional DC/DC converter for supercapacitor (SC) interfacing. The bidirectional capability provides both the charging and discharging of the SC. During the charging mode the converter operates as a conventional VSI performing the voltage buck function, but during the discharging mode the converter operates as a qZSI based step-up DC/DC converter performing the voltage boost function. The proposed converter discussed was tested in both operating modes - SC charging and discharging. Theoretical assumptions are proved by the PSIM simulation results and verified experimentally on a 500 W laboratory prototype. The most important results obtained are outlined.