Analysis, design, and implementation of switched Z‐source inverter with an extra control input

Abstract

The current study proposes a topology for switched Z‐source inverter. In the switching method used for this structure, unlike the conventional, the active network switches’ duty cycle is not equal to the shoot‐through duty cycle. So, in addition to the shoot‐through duty cycle, the duty cycle of impedance network switches is also involved in the boost factor. Besides, by extracting the small‐signal model, it is observed that the proposed topology has two control inputs on the dc‐side. The advantage of the additional control input is demonstrated by designing a closed‐loop control for the case where the inverter is used as an interface between the photovoltaics (PV) and the grid. In addition, the steady‐state analysis in different operating modes and the switching pattern are presented for the proposed topology. Comparing the number of elements and the boost factor of the proposed topology with several conventional topologies indicates that besides the control advantage, this topology has a higher voltage gain. Finally, simulation and experimental results are presented to verify theoretical discussions of the proposed inverter.