Photovoltaic grid-connected inverter sdt

In this study, a two-stage grid-connected inverter is proposed for photovoltaic (PV) systems. The proposed system consist of a single-ended primary-inductor converter (SEPIC) converter which tracks the maximum power point of the PV system and a three-phase voltage source inverter (VSI) with LCL filter to export the PV supplied energy to the grid.

Grid-interactive solar PV inverters must satisfy the technical requirements of PV energy penetration posed by various country's rules and guidelines. Grid-connected PV systems enable consumers to contribute unused or excess electricity to the utility grid while using less power from the grid.

In general, on the basis of transformer, the grid-connected PV inverter topologies are categorized into two groups, i.e., those with transformer and the ones which are transformerless. Line-frequency transformers are used in the inverters for galvanic isolation of between the PV panel and the utility grid.

Between the CCM and VCM mode of VSI, the CCM is preferred selection for the grid-connected PV systems. In addition, various inverter topologies i.e. power de-coupling, single stage inverter, multiple stage inverter, transformer and transformerless inverters, multilevel inverters, and soft switching inverters are investigated.

The different solar PV configurations, international/ national standards and grid codes for grid connected solar PV systems have been highlighted. The state-of-the-art features of multi-functional grid-connected solar PV inverters for increased penetration of solar PV power are examined.

Grid-connected PV inverters have traditionally been thought as active power sources with an emphasis on maximizing power extraction from the PV modules. While maximizing power transfer remains a top priority, utility grid stability is now widely acknowledged to benefit from several auxiliary services that grid-connected PV inverters may offer.