AC small signal modeling and analysis of Quasi-Switched Boost Inverter

Abstract

This paper presents the ac small signal modeling of Quasi-Switched Boost Inverter (QSBI). Quasi-Switched Boost Inverter (QSBI) has been recently derived from classical Quasi-Z-source converter. Both QSBI and Quasi-Z-source inverter (QZSI) are single-stage buck-boost inverter. But QSBI has some added advantages over QZSI such as reduced number of components for impedance network, lower current rating for its switches and diodes, higher boost factor, higher efficiency. The ac small signal analysis of QSBI has been done by means of state space averaging technique. Further the transfer functions have been deduced to understand the control schemes of QSBI. The transfer functions show the presence of right half plane (RHP) zero which reveals the non-minimum phase behavior of the system which shows limitations in controller design. The classical root-locus method has been used to study the RHP zero trajectories with variations in network parameters. The QSBI design guidelines for passive component sizing is investigated based on deduced transfer functions. Simulation results are being shown to validate the dynamic modeling done in this paper.