How to eliminate strong electrical coupling interference in a concentrator?

The high-voltage components (such as power modules and relay drivers) coexist with the low-voltage acquisition/communication circuits inside the concentrator. The rapid switching of the high-voltage circuits generates strong electromagnetic fields that couple to the low-voltage circuits. Eliminating this coupling requires physical isolation and shielding. Structurally, the high-voltage and low-voltage modules are placed in independent metal-shielded cavities, separated by metal partitions. These partitions are connected to the chassis with low impedance.

All signal lines crossing the partitions must pass through a filter feedthrough capacitor (e.g., 100pF/2kV) or a common-mode choke CMZ2012A-900T. In the PCB design, the high-voltage and low-voltage areas are separated by an isolation strip of at least 3mm, with a Y-capacitor (2.2nF/Y1) bridging the isolation strip. High-voltage traces (such as relay drive lines) should be shielded or wrapped with a ground guard trace on the PCB. Through the above measures, the noise voltage coupled to the weak current circuit by the operation of the high-voltage switch can be reduced from 100mV to below 5mV, and the system's radiated immunity meets the IEC 61000-4-3 10V/m requirement.