Quasi-Z-source dc-dc converter with voltage-lift technique

Abstract

Quasi-Z-source dc-dc converter has a unique LC impedance network that can output positive polar boost voltage and negative polar buck-boost voltage. Quasi-Z-source dc-dc converter has following advantages; 1) continuous input current, 2) low voltage stress on capacitors, and 3) sharing the input and output grounds. However, the input current ripple is higher than that of the traditional dc-dc converters, and the voltage gain is the same as that of the traditional Z-source dc-dc converter. This paper proposes quasi-Z-source dc-dc converter with voltage-lift technique. In the proposed circuit, one capacitor, one inductor, and two diodes are added to the conventional quasi-Z-source network. Compared with Quasi-Z-source dc-dc converter, the proposed circuit reduces the input current ripple and the voltage stress on capacitors, and has high boost voltage conversion ability. The operational principle of the proposed circuit has been confirmed by analysis and circuit experiment in steady-state.