Derivation of AC small signal model and analysis of trans Z-source inverter

This paper presents the ac small signal modeling and analysis of trans Z-Source inverter (trans ZSI). Trans ZSI has been derived from quasi Z-source converter recently. While maintaining all prominent features of pervious Z-source inverters, trans ZSI has several unique advantages such as increased voltage gain, reduced voltage stress and reduced components of impedance network. In the process of designing control schemes for the trans ZSI, knowledge of the transfer function representing its unique dc impedance network is essential. In particular, the state space averaging method is employed to deduce the transfer functions. These transfer functions reveal the presence of right half plane (RHP) zero, which imposes some limitations on controller design. The RHP zero trajectories with variations in network parameters can be studied using classical root-locus analyses. Considering system dynamic characteristics, the trans ZSI design guidelines for passive component sizing is investigated by parameter sweeping of the small signal model based transfer functions. Simulation results are presented to verify the dynamic modeling identified in this paper.