This digest presents the degradation testing and failure mechanisms analysis of metallized film capacitors used for the AC filtering in MW power converters. Based on more than 2,500 hours of accelerated testing under accelerated voltage, temperature, and ripple current, various electro-thermal parameter data are recorded. The results reveal that capacitance values have negligible reduction until the testing samples catastrophically fail. The capacitor hotspot temperature and case temperature are measured along the testing, which are increasing. The observations provide a new perspective on the possible failure mechanisms and condition monitoring of film capacitors in the AC filtering applications.
