Improved Maximum Boost Control and Reduced Common-Mode Voltage Switching Patterns of Three-Level Z-Source Inverter

The maximum boost control (MBC) technique of voltage boosting offers the highest output voltage gain among other boost control techniques of Z-source inverter (ZSI). But, this technique suffers from the major drawback of sixth fundamental frequency (6
^th
F1) ripple components of the impedance network inductor current. Due to this, the size/cost of the impedance network increases, which limits the practical applications of MBC. This article proposes an improved version of MBC via appropriate modification in the conventional space vector pulse width modulation of three-level ZSI (3L-ZSI). The improved MBC eliminates the problem of the 6
^th
F1 impedance network inductor current ripple of 3L-ZSI without affecting its input/output gain and switching stress across power switches as compared to the existing MBC. Also, two new improved reduced common-mode voltage (RCMV) switching patterns have been proposed. As compared to the existing ones, the proposed RCMV switching patterns of 3L-ZSI offers reduced size of the impedance network while limiting the common-mode voltage magnitude to one-sixth of the available dc-link voltage. The above-mentioned findings have been successfully validated using theoretical analysis, simulation, and experimental results.