During the non-isolated/transformerless inverters in parallel, there is a direct coupling relationship between the inverter circuits, and distributed parameter impedance inside transmission lines.
Recently, we shipped 100pcs 5kw on-Grid solar inverters to Americas for L-L 220Vac Grid connections! With years sampling,testing and help from Brazil/Mexico/Chile/Peru customers, we solved problems caused by differences between Americas L-L power Grid and L-N 220Vac electricity Grid, for long time stable high-efficient Grid-connection working!
As well as some 1phase 120Vac 2KW-4KW&3phase 240Vac 10KW-30KW inverters.
Our MPPT Solar charge controllers 20A12Vdc to 65A 96Vdc were installed in 2016 early at several Indian Ocean islands around Réunion for stand-alone solar power systems, bearing ocean corrective winds and moisture, But running 1.5Year until now without any fault!
And half year before, we upgraded them to 3rd generation with outside-fuses/DC-loading/wider input voltage range/max efficiency!