Communication base station inverter grid-connected transformer selection

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.

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.

To step up the output voltage of the inverter to such levels, a transformer is employed at its output. This facilitates further interconnections within the PV system before supplying power to the grid. The paper sets out various parameters associated with such transformers and the key performance indicators to be considered.

Configurations of the grid-connected PV inverters The grid-connected inverters undergone various configurations can be categorized in to four types, the central inverters, the string inverters, the multi-string inverts and the ac module inverters.

Auxiliary functions should be included in Grid-connected PV inverters to help maintain balance if there is a mismatch between power generation and load demand.