Grid Interconnected Z-Source PV System

The paper proposes the use of the Z-Source inverter for photovoltaic (PV) grid interconnection. Unlike the traditional inverter, the Z-Source inverter has two independent control variables: shoot-through duty ratio and modulation index. This paper demonstrates that the Z-Source inverter can boost dc voltage when needed, perform maximum power tracking, and interface with the grid. A Z-source inverter system is considered for a 230-400 V dc PV array's interconnection with a three-phase 208 V rms grid. Simulation results prove that the Z-source inverter can perform maximum power tracking and produce the needed ac voltage to the grid for the entire PV voltage range of 230-400 V, which is not possible for the traditional inverter without dc-dc boost converter.