Reliability oriented design of a grid-connected photovoltaic microinverter

High reliability performance of microinverters in Photovoltaic (PV) systems is a merit to match lifetime with PV panels, and to reduce the required maintenance efforts and costs. This paper applies a reliability oriented design method for a grid-connected PV microinverter to achieve specific lifetime requirement. Reliability allocation is performed from the system-level requirement to the component-level reliability design target. Special attentions are paid to reliability-critical components, e.g., GaN HEMTs and the dc-link aluminum electrolytic capacitor. A design flow chart, including key steps of mission profile based long-term stress analysis, lifetime predication, and reliability modeling are presented. A case study of a 300 W two-stage PV microinverter is used to demonstrate the design method