Does the common-mode conducted interference on the BMS control board exceed standard requirements due to poor grounding?

Poor grounding is a key cause of excessive common-mode conducted interference. Common-mode noise current requires a low-impedance grounding path to return to its source. If the grounding impedance is high, the grounding point is disorganized, or ground loops exist, noise cannot be effectively bypassed and will be conducted through cables. This leads to a decrease in the effectiveness of common-mode filter capacitors and common-mode inductors, and may even cause the chassis or cables to become radiating antennas. The solution is to establish a good, low-impedance, single-point or zoned grounding system. Connect the Y capacitor of the common-mode filter to a clean grounding point as close as possible, ensure reliable grounding of the BMS board and chassis, and use short, thick grounding wires. Good grounding provides the necessary return path for common-mode noise and is the foundation for effective filtering.