Comparison of z-source and boost-buck inverter topologies as a single phase transformer-less photovoltaic grid-connected power conditioner

In PV grid connected power conditioners; usually is required to step up the PV array voltage, and to step down the DC bus voltage for injection of a sinusoidal current to the grid. In this paper, the design procedure of the traditional double stage boost-buck inverter and single stage z-source converter, as a single phase PV grid connected transformer-less power conditioner is presented. The reduction of the component cost is a research goal in PV grid connected systems. The omission of the isolation transformer, and the usage of a single-stage z-source inverter, helps to develop a cost-effective PV-PCU. In addition, the optimum modulation method for each converter is proposed. The performances of both topologies are investigated. The energy storage elements and the efficiency of the converters are compared