The microinverter is a tiny inverter that may be mounted on each solar panel. In contrast, conventional solar inverters for strings are often mounted on a wall at some distance from the panels and linked to them by a DC wire, making this setup quite unusual. The inverter in a string inverter system converts the DC electricity from the panel string to AC power.
Read here
DC electricity is converted to AC power right there on the roof thanks to the micro Inverters connected to each solar panel, allowing each panel to function independently from the others in the array. Known as AC solar modules, there are also solar panels that come with built-in microinverters.