How to control common-mode interference of intelligent controller PAC at the source?

Common-mode interference in the PAC (Power Actuator) mainly originates from primary-side coupling of the switching power supply, ground potential difference, and cable antenna effect. Source control needs to address this from three aspects: isolation, filtering, and grounding.

Firstly, a CMZ7060A-701T common-mode inductor (700μH) paired with a Y2 safety capacitor is used in the pre-amplifier stage of the AC/DC power module to construct the first-stage filter, suppressing common-mode conduction from 150kHz to 30MHz. Secondly, an isolated power supply module, such as a DC/DC isolation module, is used, with a CMZ3225 deployed on its secondary side. The A-510T common-mode inductor blocks ground loops; all I/O ports, such as Ethernet and CAN, require common-mode filtering via CML3225A-510T or CML4532A-510T common-mode inductors; for grounding, a single-point star grounding is used, with the chassis and protective ground connected via a low-impedance connection, and the grounding wire length less than λ/20; actual measurements show that this solution can reduce the common-mode conducted interference of the PAC by 40dB in the 10kHz-30MHz frequency band, passing the IEC61000-4-6 Level 3 (10V/m) test.