Multimode Control of a Grid Interactive Microgrid With Parallel Inverters Interfacing Independent PV Arrays

This paper presents a microgrid with two parallel inverters linking independent photovoltaic arrays (PVAs) to the grid, with boost converters being the intermediate stage facilitating peak power withdrawal. Under the normal scenario of healthy distribution network, both the voltage source converters (VSCs) of the microgrid stay linked with the grid, and deliver a predefined power, regardless of the prevalent generation levels and load demands. This control over the exchanged power is made possible by the use of a battery energy storage (BES). In case an anomaly is found with the grid voltages, the microgrid is delinked from the utility network, and the main VSC switches to a grid forming operation, whereas the slave VSC operation is unperturbed. The BES stabilizes the standalone operation by acting as a source or sink, as per requirements. The main VSC also establishes transient free reconnection at grid revival. The microgrid control is resilient against non-ideal grid voltages, and also prevents the local nonlinear loads from deteriorating the grid power quality.