A Feedforward-Feedback Cascaded CM Active EMI Filter With Component Reuse

Cascaded active electromagnetic interference filter (AEF) can provide better electromagnetic interference (EMI) suppression effectiveness compared with the singlestage AEF. However, the required number of hardware components (sensors, operational amplifier, etc.) of the traditional cascaded AEF is proportionally increased with the number of AEF stages, leading to proportional rise in both volume and expense. To address this issue, this letter proposed a cascaded common-mode (CM) current-sensing current-compensating (CSCC) AEF with feedforward (FF)-feedback (FB) structure integration and component reuse. The sub FF and FB CSCC AEF in the proposed cascaded AEF share the main components, including the current sensing transformer, operational amplifier, and power supply. With the combination of FF CSCC AEF and FB CSCC AEF, the proposed AEF achieves a beneficial tradeoff between EMI attenuation and component consumption. It can provide comparable EMI attenuation to that of the traditional two-stage cascaded AEF while using a nearly similar number of main components as a single-stage AEF. Experiments conducted on boost converter verify the effectiveness of the proposed AEF.