Sensorless Active EMI Filter with Reduced Sensing Voltage and Injection Current Stress for Harmonic Mitigation in Power Electronics

Electromagnetic interference (EMI) generated by power electronic converters presents a significant challenge to increasing switching frequency and power density in modern distributed generation systems. Conventional active EMI filters (AEFs) typically rely on high-voltage sensing networks to detect conducted EMI, which increases system size and vulnerability to voltage surges. This paper proposes a novel active EMI filter (AEF) based on low-voltage mutual capacitance (LVMC), which integrates mutual inductance and active capacitance principles. The LVMC-AEF eliminates the need for high-voltage sensing capacitors and reduces the required sensing voltage and injection currents in active devices. Experimental results from EMI testing on a two-level hard-switching inverter confirm the effectiveness and advantages of the proposed topology.