This unit is intended to connect one photovoltaic (PV) panel - typically part of an array of PV panels - to a single-phase of the electric utility grid. By dealing with a single panel, we can easily implement Maximum Power Point (MPP) tracking and also create a more robust system by avoiding single-point failure. In a conventional PV panel installation, the panels are connected in series to a central inverter. In such an arrangement, if a single PV panel becomes shaded or dirty, the power output of the entire system is greatly reduced. With a microinverter, the operating point of each panel is independent of the others in the system.
This converter is based on a two-stage design. The first stage is a DC-DC converter with wide-input-voltage range and high boost-ratio. It is intended to manage the MPP of the panel and to generate a 200V bus for the inverter. The second stage is a DC-AC converter with buck-type operation. It regulates the DC bus voltage and acts as a current-source inverter.