Performance improvement method for the voltage-fed qZSI with continuous input current

This paper proposes the performance improvement method for 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 is 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 traditional solution (voltage boost and buck functions in a single stage, continuous input current and improved reliability). Moreover, the proposed solution features over the 30% shoot-through duty cycle reduction for the same voltage boost factor and component stresses as compared to conventional qZSI. Theoretical analysis of the two-stage qZSI in shoot-through and non-shoot-through operating modes is presented. The design guidelines for the two-stage qZS-network based step-up DC/DC converter are provided. A prototype has been built to verify the theoretical assumptions. The simulation and experimental results are presented and discussed.