In general,
- for a grid-tie system, we need microinverter, string inverter;
- for a off-grid system, we need charge controller, battery and DC-AC inverter.
The micro inverter is a great solution for residential or 30-50KW less commercial projects. Above all, it supports module level optimization, which can help to produce 10-15% more power.
The string inverter is good for large commercial projects, or even the power plant projects.