Reliability Evaluation of the Universal Power Electronic Interface Converter for PV Applications

This paper analyzes the reliability of the universal power electronic interface converter used for integrating PV modules and battery energy storage in residential microgrids. Its topology is based on a multi-mode isolated buck-boost series resonant converter (SRC). The converter works in a wide input voltage range of 10 to 60 V, with its output connected to a 350 V dc microgrid. To evaluate its reliability, a one-year mission profile of solar irradiance and ambient temperature of Tallinn, Estonia, was recorded. The application-specific mission profiles were synthesized for three PV module types. They were used in conjunction with the methodology based on the latest FIDES Guide to find the random failure rate and yearly degradation of the converter components. Additionally, partial shading was modeled analytically to ensure the converter operates within a wide input voltage range. An analytical loss and thermal models for the converter were designed to evaluate the thermal stresses of the components. Finally, the converter lifetime prediction was calculated for nine case studies, and the results were compared in terms of B5 lifetime.