Remaining useful lifetime estimation for degraded power MOSFETs under cyclic thermal stress

Power semiconductor devices are the major cause of the power converter failures together with the electrolytic dc bus capacitors. In harsh operating environments, the power devices are subjected to various mechanical and electrical stresses, wear, and vibration that contribute to increased equipment failure rate, where a failed component can cause unexpected interruptions, serious safety issues, or easily account for millions of dollars in repair costs. Developing prognosis tools is vital for the reliability of these systems. This paper focuses on the remaining useful lifetime (RUL) estimation of degraded power MOSFETs which are stressed by thermal cycling. The relative change in on-state resistance is identified as the fault signature. A multiple device ageing platform is designed and built to collect experimental data. An exponential degradation model that fits successfully with the experimental data is developed. The experimental data is processed with Kalman Filter, and RUL estimation with limited field data is demonstrated.