Reliability criterion of film capacitor based on moisture diffusion in encapsulation

The current reliability criterion (RC) of the film capacitor (FC) is usually a fixed value, which does not consider staged capacitance loss caused by moisture diffusion under high temperature and/or humidity. expected lifetime capacitors would deviate far from actual one. process encapsulated FC analysed based on Fick's second law. In order to investigate and characteristics, 4 types are stressed with AC voltage different temperatures humidities. Based analysis weight gain curves, effect revealed. Results indicate that linear stage corresponds Fickian gain. aging most significant. rate increases 301% when rises 30%. An RC calculation method further proposed, could also screen encapsulation quality shorten test duration at least 80%.