Switched Quasi Z-Source DC-DC Converter For Photovoltaic System

The depletion of fossil fuels worldwide is driving the acceleration of renewable power energy systems, particularly those based on photovoltaics (PV). To enhance the voltage output from PV electricity systems for grid-linked inverters, a dc-dc boost converter can be employed. However, traditional boost converters face various challenges, leading to the proposal of several configurations aimed at improving their boosting capabilities. One such configuration is the Quasi impedance (Z)-source dc-dc converter, derived from the conventional impedance (Z)-source converter by incorporating a switch and diode at the output terminals. Compared to existing Z-source configurations, this converter operates with a small duty cycle (less than 0.25), resulting in a higher boosting factor and avoiding instability caused by inductor saturation. Moreover, it requires fewer passive components, leading to reduced losses, increased power density, and cost reduction. This paper discusses the features of the proposed converter and its functioning in continuous current conduction mode.