Small-Signal Modeling of Open-Loop PWM Z-Source Converter by Circuit-Averaging Technique

Abstract

This paper presents the ac small-signal modeling of the power stage of pulsewidth-modulated Z-source converter in continuous conduction mode by the circuit-averaging technique. The small-signal models used to derive the open-loop power-stage input voltage-to-capacitor voltage, input voltage-to-inductor current, control-to-capacitor voltage, and control-to-inductor current transfer functions are derived. Open-loop power-stage transfer functions corresponding to the capacitor voltage loop and inductor current loop are derived. The transfer functions derived take into account the equivalent series resistances of the inductors and capacitors. Experimental validation of the derived small-signal models is presented for a laboratory prototype. The theoretical predictions are in good agreement with the experimental results.