Despite the emerging multi-phase and multi-level converters, two-level insulated gate bipolar transistor-based power converters are still widely used in industrial applications in nowadays. Thus, its reliability is of significant importance for ensuring industrial safety. In this paper, a review of the possibilities to ensure the reliable operation of these power converters is presented. The possible approaches are categorized into two groups: condition monitoring and fault-tolerant control. The former approach performs the monitoring methods of power converters, which enables the identification of device degradation to be realized. Accordingly, the mechanisms, indicators, and measuring methods of degradation are demonstrated in this paper to assist the design of condition-based maintenance. In contrast, the latter approach is a postfault one, where power converters remain the operation by activating the fault-tolerant units after faults are identified. For this approach, fault detection, fault isolation, and tolerant strategies are essential. Finally, the performance and cost-effectiveness of the two categories are discussed in this paper. INDEX TERMS Two-level power converter, reliability, condition Monitoring, fault tolerance, renewable energy application, insulated gate bipolar transistor.

With the rapid development of high-speed railways, fault detection and diagnosis for traction transformers are more and more important, and the detection method with high accuracy is the key to assure the normal operation of the traction power supply system. A method based on kernel principal component analysis (KPCA) and random forest (RF) is proposed to diagnose the traction transformer faults in this study. In this method, KPCA can obtain more fault characteristics in high-dimensional space through the non-linear transformation of the original data with dissolved gas analysis, and RF can utilise these characteristics to construct the classifier group. The experimental results show that the combination of KPCA and RF can effectively extract more characteristics of traction transformer faults to construct the classifiers with better performance, which contributes to the higher accuracy in traction transformer fault diagnosis and gets better anti-jamming performance.

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Abstract:In this paper, a diagnosis plan is proposed to settle the detection and isolation problem of open switch faults in high-speed railway traction system traction inverters.