Quasi –Z- Source Inverter for Photovoltaic Power Generation

Abstract: Quasi Z-source inverter is a recently developed topology derived from Z-source inverter (ZSI) which is capable of boosting action along with inversion. QZSI is a one-stage power conditioner that employs a capacitor-inductor network for connecting inverter to photovoltaic module. By means of controlling shoot-through duty cycle, the objective of tracking maximum power point can be accomplished. In comparison with ZSI, QZSI benefits some prominent privileges such as lower component ratings and source constant dc current. In this paper, through introducing an appropriate control structure, QZSI is used for connecting photovoltaic system to single phase grid. In the control structure, maximum power with unity power factor and low THD current is delivered to grid by controlling modulation index via PI controller. The proposed system is verified by using MATLAB/Simulink. Keywords: Quasi Z Source inverter, Shoot -through duty ratio, Maximum power point tracking, Grid connected inverter.