Real-Time Estimation of Film Capacitor Lifespan in Modular Multilevel Converters

Film Capacitors are widely used in modular multilevel converter (MMC) systems due to their high reliability and long-life characteristics. However, the degradation of film capacitors vulnerable to humidity and temperature can reduce the MMC system’s dependability. Since it can be tricky to anticipate variations in humidity and temperature and the aging model-based external stress mission profile may lead to significant deviation, this paper proposes a remaining life estimation methodology by fusing real-time updated degradation data. In the proposed methodology, a quadratic polynomial is used to fit the aging curve of capacitor based on the degradation data. Because the proposed method is a dynamic scheduling algorithm, it is free of external stress. The effectiveness of the proposed method is verified, and the results show that it has a good performance.