Reliability Modeling and Assessment of De-rated Redundant Power Converters

This paper proposes a reliability modeling approach and a reliability measure for redundant power converters with the possibility of de-rated operation. The proposed model takes into account the operating condition and its impact on the converter failure rate. Furthermore, the proposed reliability index is based on an availability measure, hence incorporating the impact of maintenance on the converter performance. However, the conventional reliability modeling approaches rely on either the probability of failure or availability based on the average failure rate. As a result, the proposed method introduces more accurate and realistic reliability performance. The proposed model is applicable for reliability assessment in power electronics systems for expert decision-making in asset management. The proposed approach is examined using a multi-level converter and a proper control system is proposed to operate the converter under de-rated operating conditions. The numerical analysis shows the proficiency of the proposed reliability modeling approach.