Development and Reliability Assessment of Si and SiC Power Devices-Based Solid-State Transformer for Urban Railway Vehicle

A solid-state transformer (SST) is regarded as a promising alternative to conventional low-frequency (LF) transformers in railway vehicles. Through SST, efficiency improvement and reduction of weight and volume can be achieved. On the other hand, the cost and reliability are the main concerns of an SST over an LF transformer. Nevertheless, there is a lack of study on the reliability of SST in the state-of-the-art research. In this article, an SST for urban railway vehicles is designed by considering different aspects, such as cost, efficiency, weight, and volume depending on the number of SST modules. Then, a full-scale prototype of Si and SiC power devices-based SST modules is developed and its operation is experimentally verified. Finally, the system-level reliability of the designed SST is assessed based on two real mission profiles of urban railway vehicles by focusing on the lifetime of different power devices.