Analysis and Design of a Zero-Current Switching Non-Isolated High Gain Inverter

Abstract

High gain inverters are gaining popularity due to their application in renewable energy sources. Impedance source inverters (ISIs) such as Z-source inverter (ZSI) and its derivatives are favored over the two-stage boost-VSI topology because of their higher gain and better EMI immunity. Another ISI, Current-fed Switched Inverter (CFSI), has a similar gain characteristic as ZSI but with lesser components. The major drawback of high gain inverters is that they draw very high input current. Thus, the switching and conduction losses increase in the front stage converter, resulting in reduced efficiency. This paper proposes a modified CFSI topology to achieve Zero Current Switching (ZCS) of the switch connected in the front-end boost stage. The operating principle and modes of operation of the proposed converter are discussed in detail. A flow chart for designing the resonating components of the modified circuit and the impact of parametric variation on the scheme's performance is reported. The theoretical analysis is verified with the help of a laboratory prototype. The efficiency of the modified converter is found to be increased by 2% (at 450 W load) compared to conventional CFSI.

Keywords

• Current-fed switched inverter (CFSI)
• PWM
• inverter
• soft switching
• ZVS
• ZCS