Double‐fed and double‐switch active Z‐source inverter with general variable high boost factor

Abstract

In this study, a new topology for Z-source inverter is proposed without adding additional passive elements to the conventional impedance network. The proposed topology is double-fed and can generate high voltage gain in comparison with the conventional Z-source inverters. By using improved simple boost modulation technique, the function of boost factor in the proposed inverter is general and variable. In other words, not only the boost factor of the proposed inverter depends on value of shoot-through (ST) duty cycle but also is dependent on the value of switching factor and controllable by changing specific signals in switching pattern. In this study, steady-state analysis of the proposed inverter in different operating modes such as ST operating mode, adjacent-non-ST (A-nST) operating mode and non-A-nST operating mode are presented. Design considerations and critical inductance between proper and improper operations are calculated. Then, the used modulation technique and switching pattern are investigated and comparison between the proposed and conventional inverters from different points of view is done. Finally, simulation results using PSCAD/EMTDC software and experimental results are presented to verify theoretical discussions, derived equations and correct operation of the proposed inverter.