Extended Boost Switched-Embedded-Capacitor-Inductor ZSI with Low Voltage Stress on Capacitors and Soft-Start Capability

Abstract

ABSTRACT In the present article, the boost factor of the Z-source inverter is noticeably increased by using the switched-inductor structure. The proposed inverter is based on the switched-inductor Z-source inverter which has two series diodes in its switched-inductor. In the proposed ZSI instead of these two series diodes, two capacitors are used. In comparison with the conventional structure, in the smaller duty cycle ratio the proposed structures generate higher voltage. Besides, in the second proposed structure to reduce the voltages on the capacitors of the Z-source network, a dc source is placed between the inverter bridge and the Z-source network. The dc source and the inverter have common ground in both the proposed structures. The conventional and proposed inverters are thoroughly investigated to find out their governing relations, then, the boost factor and voltage across capacitors in both proposed and conventional inverters are compared with each other by simulating them in PSCAD/EMTDC. Next, the prototypes of the proposed inverters with 25 V dc input voltage are used to evaluate the obtained results.