Practical Approach in Designing Conducted EMI Filter to Mitigate Common Mode and Differential Mode Noises in SMPS


Fast switching in SMPS generate large amount of Electromagnetic Interference (EMI). The EMI consists of mainly common mode and differential mode noises. In the present work, conducted EMI is studied and a procedure for designing AC power line filter is proposed. As an application of this design procedure, conducted EMI noise measurement and filter design of a boost AC-DC converter with PFC has been achieved while successfully satisfying the CISPR22/EN55022 limit in the frequency range from 150KHz to 30MHz, which confirms the validity of the design procedure.