Analysis of PWM Z-Source DC-DC Converter in CCM for Steady State

Abstract

Steady-state analysis of pulse-width modulated (PWM) Z-source dc-dc converter operating in continuous conduction mode (CCM) is presented. Voltage and current waveforms, and their corresponding expressions describing the steady-state operation of the PWM Z-source dc-dc converter have been presented. The input-to-output dc voltage transfer functions, both for ideal and non-ideal PWM Z-source dc-dc converter have been derived. The minimum Z-network inductance required to ensure CCM operation is derived. The voltage ripple due to filter capacitor and its ESR, and their individual effects on the the overall output voltage ripple have been derived and analyzed. Expressions for power loss in each of the components of the PWM Z-source dc-dc converter has been determined. Using the expressions derived to determine the power losses, an expression for the overall efficiency of the PWM Z-source dc-dc has been derived. An example PWM Z-source dc-dc converter is considered. A laboratory prototype is built and the theoretical analysis is in good agreement with the experimental results.