Small-signal modeling of PWM Z-source converter by circuit-averaging technique

Abstract

This paper presents the small-signal modeling of pulse-width modulated (PWM) Z-source converter (ZSC) operating in continuous conduction mode (CCM) by circuit averaging technique. The averaged large-signal, dc, and time-invariant linear small-signal circuit models of PWM ZSC power stage operating in CCM are derived. The small-signal modeling focuses on the dynamics introduced by the Z network present in the ZSC. Based on the small-signal model derived, the small-signal model required to derive the open-loop input-to-capacitor voltage transfer function is derived. The open-loop input-to-capacitor voltage transfer function is derived, and the associated theoretical Bode plots are illustrated using Matlab and is verified by circuit simulation. The theoretical results were in excellent agreement with the simulation results, validating the ac small-signal model and the derived input-to-capacitor voltage transfer function.