Impact of component losses on the voltage boost properties and efficiency of the qZS-converter family

This paper is devoted to the quasi-Z-source (qZS) converter family. Recently, the qZS-converters have attracted high attention because of their specific properties of voltage boost and buck functions with a single switching stage, which could be especially advantageous in renewable energy applications. As main representatives of the qZS-converter family, the traditional quasi-Z-source inverter as well as two novel extended boost quasi-Z-source inverters are discussed. Steady state analysis of three main topologies operating in the continuous conduction mode is presented. Input voltage boost properties of converters are compared for an ideal case. Mathematical models of converters considering losses in components are derived. Practical boost properties of converters are compared to idealized ones and the impact of losses on the voltage boost properties of each topology is justified. Finally, the impact of losses in the components on the boost conversion efficiency is analyzed.