Optimization of Impedance-Source Galvanically Isolated DC–DC Converters With Reduced Number of Switches

Abstract

In this study, a new type of Z-source converter comprising galvanic isolation transformers is introduced based on classical non-isolated Z-source converters, which are promising devices for renewable applications. Compared to the typology of conventional converters with isolation transformers, the proposed converter topology has a simpler structure with fewer power switches and lower costs. Considering the lower number of switching devices required in the proposed typology, these efficiency and reliability of the presented converters are higher than those of the conventional ones. As only one switch is used in the developed structure, voltage stresses on the Z-source converter decreases in each period, which maintains voltage stress low and steady across the switch. Another desirable feature of the proposed topology is reduced converter size and volume with a maximum theoretical and practical efficiency of 97 to 94.05%, respectively. Moreover, these converters need low input voltage and provide the required amount of output voltage in small duty cycles. The theoretical and operational analysis of the designed converter and its comparison with other counterpart converters (e.g., isolated Z-source converters) is presented. The simulation and experimental results confirm the applicability of the proposed system.

Keywords

• Galvanic isolation transformer
• DC-DC power converter
• Z-source network
• simulation analysis
• reduced switches