A generalized control approach for photovoltaic grid-tie microinverters

In this paper, the design of a microcontroller-based control scheme for grid-tie photovoltaic (PV) microinverters using Direct Digital Synthesis (DDS) technique has been presented. The proposed control scheme based on DDS technique has capabilities such as, phase locked-loop generation, maximum power point tracking, anti-islanding and fault ride-through capability, which are essential requirements for a grid connected inverter. These features can satisfactorily be integrated within the software of a low cost microcontroller, thus resulting in a generalized and flexible system. This control scheme, when applied to a microinverter, meets all the required functions of a PV grid-tie microinverter.