Stability Analysis of Improved Y - Source Inverter

The improved Y-source inverter (YSI) not only inherits the advantages of YSI, such as a simple structure, high voltage gain and low operating stress, but also solves the problems that the input current is discontinuous and mitigates the interference resulting from the leakage inductance. In recent years, Y source impedance network has become the main research direction of many scholars. Up to now, steady state and DC characteristics of improved YSI have been investigated in numerous articles. However, modeling analysis for improved YSI is rarely presented. It should be noted that due to the effective role of system modeling in closed-loop controller design, the modeling of improved YSI is critical. In this paper, a small-signal model of improved YSI with LC filter based on state-space averaging method is established. The transfer functions in continuous conduction mode (CCM) are further analyzed. Finally, in order to demonstrate the effect of circuit parameter variations on the system stability of improved YSI, the placement of poles and zeros of transfer functions is analyzed.