Operational analysis and performance comparison of current-type Z-source inverters

This paper presents the operational analysis and performance comparison of various current-type Z-source inverters. With an X-shaped LC impedance network added, all current-type Z-source inverters can perform current buck-boost operation with expected output performance except of the case where modulation index is tuned to be lower than the physical boundary between linear modulation and distorted operation regions. Both mathematical derivation and hardware solution for smooth modulation are hereby presented. In addition to the common limitation of all current-type Z-source inverters, their performance mainly with regard to the losses of impedance network is analyzed by considering the different value of inductive conduction current. All theoretical findings are verified by PLECS simulation and experimentally using a constructed laboratory prototype.