High frequency transformer isolated cascaded Quasi-Z-source inverter

There are many researches on Z-source/Quasi-Z-source inverters since the topology was proposed in 2002 by Professor F.Z. Peng. This inverter can cover the shortage of traditional inverters. Almost all of the researches are studied in a circuit structure of single-stage. The original Z-source/Quasi-Z-source cannot achieve electrical isolation between input and output. The high frequency transformer isolated Z-source/Quasi-Z-source inverter proposed by F.Z. Peng in 2011 completes and perfects the circuit topologic family of Z-source inverter. It integrates the Z-source impedance network into the two-stage DC-DC-AC inverter by high frequency transformer. This paper makes an in-depth study of high frequency transformer isolated cascaded quasi-Z-source inverter. First the paper analyzes its basic principle and an abnormal working state discontinuous conduction mode (DCM). Based on the formulas, the paper gives some advice of how to choose desirable component parameters and working parameters. At last the paper gives a simulation of the inverter working in photovoltaic power generation system.