T24.9 - Aging of Y-Capacitor in an EMI Filter and Its Impact on Common-Mode Noises

This paper investigates the effects of Y-capacitor aging on passive electromagnetic interference (EMI) suppression filters. Due to the wide adoption of WBG switches, modern power systems are subjected to severe EMI noise, risking electromagnetic compatibility (EMC). Any commercial and military power electronics system must meet EMC. Discrete passive components-based EMI filters are commonly adopted to suppress common mode (CM) and differential-mode (DM) EMI. These filters comprise common-mode choke (LCM), X-capacitors (CX), and Y-capacitors (CY). Capacitors are prone to degradation due to constant voltage stress and temperature variation. Several studies have identified the changes in capacitor parameters due to aging, which can significantly impact EMI filter attenuation capabilities. This paper focuses on the aging of CY capacitors and its effects on CM EMI attenuation of EMI filters. Simulation modeling and experimental test results up to 300 hours are presented. The impact of CY degradation has been analy