Is there a risk of exceeding the standard for differential-mode conducted interference on the BMS control board in the 2MHz-30MHz frequency band?

The 2MHz-30MHz frequency band is a high-risk area for differential-mode conducted interference, especially for switching power supplies in BMS. The risk of exceeding limits depends primarily on the input filtering design. If the front-end relies solely on a common-mode inductor, differential-mode noise suppression is insufficient. An independent differential-mode filtering stage is needed, such as using a differential-mode inductor with X and Y capacitors to form a π-type filter. In this frequency band, high-frequency characteristic MLCC capacitors should be connected in parallel to compensate for the parasitic inductance effect of electrolytic capacitors. Simultaneously, the input filtering circuit must be placed close to the port, the grounding path of the filter capacitor should be short and thick, and the differential-mode current loop area should be minimized as much as possible. A carefully designed differential-mode filter is key to reducing the risk of exceeding limits in this frequency band.