A Survey of CM EMI Modeling and Reduction Technique of Transformer for Isolated Converters

The CM modeling method and EMI reduction method of a transformer are important for isolated converters to meet EMI requirements. In this survey, the CM modeling methods for the transformer are systematically summarized first based on the effective frequency range from lowfrequency to high-frequency. Their advantages and disadvantages are also detailed compared. Furthermore, the CM EMI reduction methods for transformers are reviewed and compared. Finally, two potential research issues are defined, and preliminary research approaches are given with the analysis of the previous reviews.