A compact and efficient design of the EMI filter is critical to achieving the full benefits of electrification in highly constrained automotive system environments. CM filters for automotive OBC applications typically have limited Y-capacitance due to touch-current safety requirements and thus require large-sized CM chokes to achieve the required attenuation – ultimately resulting in filter designs with bulky, heavy and expensive passive components. This presentation describes an AEF circuit using a standalone integrated circuit for CM noise mitigation in a three-phase OBC. Practical results to suppress the measured CM noise signature indicate a significant volumetric reduction of the CM choke components. The results illustrate the key benefits available to designers in terms of EMI mitigation, reduction of choke size and cost, along with improvement in efficiency and thermal performance.
