APPLICATION OF QUASI-Z-SOURCE INVERTER IN PHOTOVOLTAIC GRID-CONNECTED SYSTEMS

الملخص

In this paper, a single phase quasi-Z-source inverter with maximum power point tracking (MPPT) is proposed for photovoltaic (PV) system. A boost DC-DC converter is used to implement the MPPT algorithm for tracking the maximum power from a PV panel. Perturb& Observe (P&O) method is used as a maximum power point tracker due to its simplicity. The suggested quasi-Z-source inverter employs the quasi-Z-source network and only two active switches to achieve the same output as the traditional voltage-fed full bridge inverter does. The proposed quasi-Z-source inverter has small size, lower cost and high efficiency since no any transformer is used (the input dc source and the output ac voltages share the same ground). Nonlinear sinusoidal pulse width modulation (SPWM) is used to produce sinusoidal inverter output voltage .Power simulation (PSIM) program is used for simulation and the obtained results show the validity of the proposed DC-AC conversion system.