An inverter is a vital electrical device in solar PV system. It transforms direct current(DC) into Alternating current (AC). For solar energy systems, this means the DC current generated from the solar panel array is input through an inverter and output to AC. This conversion is necessary to operate most electric devices or interface with the electrical grid. Inverters are widely applied to almost all solar energy systems and are typically the most expensive component apart from the solar panels.
The conversion efficiencies differ due to difference of quality. Generally 90% or higher is a good number for most inverters. Some of the the inverters contain safety protection features like anti-islanding and ground fault circuit interruption. These protection function will shut down the PV system if loss of grid power is detected.