Mission-Profile Based Reliability Framework for Medium-Frequency Transformers

This paper presents a theoretical framework for assessing the reliability of medium-frequency transformers by dividing their structure into dielectric regions and forecasting their lifetime based on mission profiles. The framework incorporates random failure and wear-out analysis to estimate reliability, highlighting specific failure mechanisms associated with high-frequency switching and insulation stresses. A case study of a 200 kW, 15 kHz dual active bridge converter is presented to demonstrate the proposed methodology. The derived lifetime distribution can support the design of the medium-frequency transformer and help evaluate the related risk of unreliability.