The inverter is the core power conversion component of a solar PV system, converting variable DC output from the PV array to AC power at the frequency and voltage required for grid connection. Inverter selection affects system efficiency, monitoring capability, grid compliance, and response to partial shading. Most commercial systems use string inverters, with microinverters used in some distributed applications.
For grid-connected systems in the UK, inverters must comply with Engineering Recommendations G98 or G99, including anti-islanding protection to disconnect from the grid in the event of a grid fault. G98 or G99 compliance is confirmed by inverter type testing, and only type-tested models should be specified for MCS-certified installations.