Common-mode and Differential-mode Equivalent Circuits for EMI Analysis in Boost Converter

This paper presents common-mode (CM) and differential-mode (DM) equivalent circuits of a boost converter. It can accurately reveal the characteristics and behavior of CM and DM voltages generated by the boost converter. The analysis considers the boost converter’s circuit following the boost converter’s switching pattern. The CM and DM equations are synthesized to form the CM and DM equivalent circuits. They show the CM and DM voltage appearing at any point of the boost converter accurately and clearly. The proposed CM equivalent circuits disclose that an unbalanced boost converter and a balanced boost converter have CM voltage at the input of the boost converter differently. The CM voltage generated from the balanced boost converter has a high dv/dt value, affecting higher EMI noise. The proposed equivalent circuits can be used as a guideline for EMI analysis and designing filter circuits to resolve EMI problems for other circuits in the future.