Considerations on grounding possibilities of Transformerless grid-connected photovoltaic inverters

Nowadays, the efficiency of commercial converters used to connect the photovoltaic (PV) panel to the utility grid can touch the value of 99%. It means that the efforts to increase the global efficiency of a PV system are diversified to other aspects of the system structure, this new design line focus on low cost, size and global losses. Besides, there some standards (isolation, PV panel grounding) and module technology requirements conduct the converter design to a more particular level. Transformerless PV inverter may have leakage current at the grounding point, while PV inverters with the transformer bring additional losses. This paper presents a general view of the technologies of the PV cells. Followed by a survey of the different possibilities of the ground point and showing the respective topologies for each case. Finally, an experimental result is performed, in order to shape the upcoming of grid-connected PV converter necessities.