Enhanced boost quasi-Z-source inverters with active switched-inductor boost network

Abstract

This study proposes a new family of high-boost-quasi-Z-source inverters (qZSIs) with combined active switchedinductor boost network. The proposed inverter provides continuous input current and higher-boost voltage inversion capability, shares common ground between the input source and the inverter bridge, which would be applicable for the renewable energy system with low-voltage distributed dc sources. In comparison to the traditional high-boost non-coupled-inductor-type qZSIs, for the same total number of passive/active components used at the impedance network, the proposed topology has higher modulation index with improved output voltage waveform quality, and lower switching voltage stress across the power switches. To produce the same voltage boost factor with the same dc input, the proposed inverter uses smaller inductance values compared with the conventional topologies. Thus, the size and weight of the passive components in the proposed topology can be reduced. This study presents the operating principles, power loss analysis, simulation results and characteristic comparison with those of the traditional high-boost qZSIs. Finally, a laboratory prototype based on the TMS320F28335 digital signal processor with 60 V dc input and 110 Vrms ac output was constructed to verify the effectiveness of the proposed inverter.