A Simple Online Fault Location and Tolerant Control Strategy for Power Electronic Transformers with a Single IGBT Open-Circuit Fault

Power electronic transformers (PETs) contains numerous power electronic modules and multiple power conversion stages, potentially leading to an increased failure rate. The complex impacts of IGBT faults and strong coupling between power conversion stages make it difficult to accurately locate faults using traditional methods designed for single stage converters. To address this challenge, a simple method to locate and tolerate a single IGBT open-circuit fault of PETs is proposed, by integrating and synthesizing the dynamic characteristics of measurement signals of PET and key node information of the controller loops. The proposed method is easy to implement without using additional sensors, and it can transfer between normal operation and fault tolerant operation without noticeable inrush current or voltage. Experimental tests validate the effectiveness of the proposed approach.