A stacked full-bridge microinverter topology for photovoltaic applications

Abstract

Previous work has been done to develop a microinverter for solar photovoltaic applications consisting of a high-frequency series resonant inverter and transformer section connected to a a cycloconverter that modulates the resonant current into a single-phase 240 VRMS utility line. This thesis presents a new stacked full-bridge topology that improves upon the previous high-frequency inverter section. By utilizing new operating modes to reduce the reliance on frequency control and allowing for the use of lower blocking voltage transistors, the operating frequency range of the HF inverter is reduced and efficiency is increased, especially at low output powers and lower portions of the line cycle. The design of an experimental prototype to test the stacked full-bridge HF inverter topology is presented along with test results that demonstrate the success of the topology. Future improvements to increase performance are also suggested.