High Voltage Gain q-ZSI with Low Inrush Current

Abstract

The high amount of inrush current that flows during the initial run-time of a classical ZSI/q-ZSI has been a major problem in the field of energy converters, owing its existence mainly to the use of dc-link capacitors in the design. This paper proposes a modified L-Z source inverter (L-ZSI), which offers a high voltage gain and eliminates the use of the dc-link capacitors. The proposed topology uses a Switched Inductor (SL) structure, containing a capacitor in series with the inductors. This capacitor helps in absorbing voltage spikes appearing across the dc-link voltage due to sudden changes in inductor current in the non-shoot through state. Moreover, being in series with the inductors, the capacitor also reduces the inrush current flowing through the switched structure circuit. Additionally, this topology offers a common ground for the input dc source and the main inverter circuit. Thus, the proposed topology provides an increase in voltage gain an overall reduction in weight, volume and cost of the inverter. These results from the derived network were validated in a MATLAB/Simulink generated environment, and then on an experimental prototype.