Reduced Output Swing Capacitance Multiplier for Common-Mode EMI Filtering in Traction Inverters

The transition from silicon to WBG-based designs in the automotive field has enabled increased power density, which, in turn, leads to a requirement of smaller and smaller Electromagnetic Interference (EMI) filters. In this context, Active and Hybrid EMI Filters (AEF/HEF) have become increasingly popular. However, when dealing with high-voltage systems, the required amplifier output voltage swing can be significant, requiring a high supply voltage, which leads to demanding design constraints. To tackle this issue, the present paper proposes a novel technique to decrease the amplifier output voltage swing. The technique is based on the suppression of the fundamental switching component, with the aid of a notch filter inserted in the interference sensing branch. The proposed technique is validated through experimental tests, showing that the amplifier output voltage swing is reduced by more than 4 times with respect to the conventional design.