This paper firstly reviews the failure causes, modes and mechanisms of two major types of
capacitors used in power electronic systems—metallized film capacitors and electrolytic
capacitors. The degradation modeling related to these capacitors is then presented. Both
physics-of-failure and data-driven degradation models for reliability and lifetime estimation
are discussed. Based on the exhaustive literature review on degradation modeling of
capacitors, we provide a critical assessment and future research directions.