The grid-tied and off-grid ESS supports a maximum of three SUN2000-(2KTL-6KTL)-L1 inverters (with batteries) cascaded. In this scenario, the inverters can be connected to the grid only at the same phase and controlled only by a single-phase power meter. . How many multi-functional grid-connected inverters are there? In 4 Multi-functional grid-connected inverters in single-phase system, 5 Multi-functional grid-connected inverters in three-phase system, the available topologies and control strategies of MFGCIs are comprehensively reviewed for. . Solar-plus–battery storage systems rely on advanced inverters to operate without any support from the grid in case of outages, if they are designed to do so.