A Comparative Analysis between Z-Source and Quasi-Z-Source Inverters for Boost Operation

This paper presents a comparative analysis between two DC-AC converter topologies known as the z-source inverter (ZSI) and quasi-z-source inverter (Q-ZSI). In terms of functionality, the Q-ZSI operates similarly to the ZSI, whereby it is able to realize buck-boost inversion and power conditioning in a single stage with improved reliability. Additionally, the Q-ZSI shares the same pulse-width modulation (PWM) shoot-through methods with the ZSI for boost control. Although both topologies consist of many similar traits, it is discovered that there are inherent differences in their transient output characteristics. Using PSCAD/EMTDC simulation environment, experiments are performed on the ZSI and Q-ZSI in order to analyze their transient responses at different boost factors. This includes the characteristics of inrush current and ripple. The acquired simulation results have exhibited several unique merits of the Q-ZSI when compared to the ZSI during boost operation.