A Robust Health Monitoring Method for DC-Link Capacitor Banks in Aerospace Motor Drives

This paper presents a health monitoring scheme for DC-link capacitor banks in aerospace motor drives, implemented through the standard post-landing discharge operation of the motor drive. The capacitance percentage of the DC-link capacitor bank relative to its healthy baseline is directly evaluated using solely the DC-link voltage profile without additional hardware upgrades or complex computations, minimizing cost and complexity concerns. Furthermore, to ensure monitoring reliability and effectiveness, practical implementation solutions are provided to address challenges arising from varying operating conditions and unbalanced capacitor degradation within the bank. Compared with existing methods, the proposed scheme offers superior practical deployability and operational robustness. Experimental validation through component-level accelerated aging tests and converter-level discharge tests demonstrates capacitance percentage evaluation error within 0.6 %, and reliable detection of critical degradation in individual capacitors within the DC-link capacitor bank under varying operating conditions, enabling proactive maintenance before failure occurs.