Cascaded switched-inductor and taped-inductor Z-source inverters

Abstract

Z-source inverter is a recently proposed single-stage inverter with added voltage-boost capability for complementing the usual voltage-buck operation of a traditional voltage-source inverter. In spite of that added feature, the overall voltage gain might still be relatively low for certain applications like the grid connection of low-voltage renewable sources that might not favor multiple series connection. To enhance its gain, while yet preserving its voltage-buck flexibility, modifications to the traditional Z-source inverter are now proposed to develop a new family of cascaded switched-inductor and tapped-inductor Z-source inverters. Unlike existing techniques, voltage stresses within the proposed inverters are better distributed among the passive components, hence avoiding likely single points of failure. For verifying these performance findings, experimental testing on a number of implemented laboratory prototypes was performed with the results shown near the end of the paper.