Two-stage quasi-Z-source network based step-up DC/DC converter

This paper presents an optimization possibility of the voltage-fed continuous input current quasi-impedance source inverter (qZSI) by the introduction of the two-stage quasi-Z-source network (qZS-network). The two-stage qZS-network could be derived by the adding of one diode, one inductor and two capacitors to the traditional qZSI. The proposed two-stage qZSI inherits all the advantages of the traditional solution (voltage boost and buck functions in a single stage, continuous input current and improved reliability). Moreover, the proposed solution features over 30% shoot-through duty cycle reduction for the same voltage boost factor as compared to the conventional qZSI. Theoretical analysis of the two-stage qZSI in shoot-through and non-shoot-through operating modes is presented. The proposed and traditional qZS-networks are compared. A prototype has been built to verify the theoretical assumptions. The experimental results are presented and analyzed. Finally, a further optimization method of the proposed two-stage qZS-network is discussed.