High density EMI mitigation solution using active approaches

Passive EMI filters occupy significant volume in a power converter. This work involves the study of utilizing Active EMI Filters (AEF) and Hybrid EMI Filters (HEF) to reduce the volume of passive filters. The DUT under consideration is a 30 W AC-DC converter. Since the power level less than 65 W it does not have a PFC stage. In this work, noise sensing is carried out using voltage sensing methodology. The applicability of the sensing method to sense noise and its relation to the maximum possible attenuation is studied. Noise sensing networks comprising the high voltage capacitors and high pass filter networks to are designed for sensing noise on AC and Dc side. For noise cancellation, feedback control scheme with both voltage and current cancellation topologies are employed separately. The possible value reduction of passive components for both topologies of AEF are identified.