Reliability Assessment of Power Converters with Partial Redundancy and Variable Power Distribution

Conventional reliability assessment method mainly consists of three steps: building component-level reliability model, establishing system-level reliability model and assessing the reliability by reliability metrics. However, this traditional method have some limitations for power converters with partial redundancy and variable power distribution: for the component-level reliability analysis, it is very difficult to determine the importance of the component failure rate; For the system-level reliability analysis, the existing models do not work well for the power converters with partly redundant components; For the conventional reliability metrics, the converters reliability cannot be fully described when the power distribution of the converters varies. In order to solve these problems, three improvements are proposed by this paper. Firstly, failure rates of all components are compared and the important ones are chosen. Secondly, a system-level reliability hybrid model, which considering partial redundancy, is proposed. Thirdly, a new reliability metric MTTFr is presented to evaluate the reliability with variable power distribution. In this paper, a compact motor drive of the electric vehicle is utilized to validate the superiority of the proposed improvements.