The objective is to develop an autonomous control scheme for grid-interfaced, series-connected low-voltage microinverters. As low-voltage microinverters generate a fraction of the grid voltage at the output, they are series connected to interface to the grid. This eliminates the need for a high step-up stage in conventional microinverter. Since simple current control is not possible in series-connected modules, an autonomous control scheme is developed which achieves MPPT in almost all cases. A second control scheme devised operates all modules with equal output voltage, in situations where some modules have significantly less power than others and MPPT is unachievable.
