Photovoltaic grid-connected system, with the inverter with the role of transformer. In the choice of inverter with a transformer and without a transformer, how should choose? That is the isolation, I do not quite understand. Who knows that high! Thank you!
Inverter with a transformer is played a role in isolation, it can provide you with pure sine wave current, so that the PV grid-connected system can provide a more secure and reliable isolation.
Select the inverter, then the election from the output waveform, preferably not lower than the quasi-sine wave; Secondly, the inverter should have a complete circuit protection; third, manufacturers have a good after-sales service commitment; And the product after a period of time.
Specific differences:
1 inverter in the transformer is mainly from the role of pressure, is to make the power can be issued directly to the low-voltage power grid. Single-phase transformer is the transformer to 230V or so, slightly higher than the electricity single-phase power; three-phase change to about 400V, is also slightly higher than the electricity three-phase power
2 some transformers in addition to the role of isolation and isolation, the inverter is dependent on IGBT power devices to inverter, these power devices will produce more 3 harmonics and 3 times the number of harmonics, these harmonics on the grid Pollution is more serious, plus the isolation transformer (once for the triangular connection, the second star connection) can effectively filter 3 times 3 times the harmonic.
3 from the role of isolation is the abnormal situation when the grid will not put the inverter's important components burned.
4 plus the transformer certainly higher prices, the other weight increases, the efficiency will be slightly reduced.
