How to improve the conducted immunity CS of frequency converters

Improving the conducted immunity of a frequency converter focuses on preventing interference currents from coupling into internal sensitive circuits through power and signal lines. Conducted immunity testing injects interference signals directly into the circuitry. Improvement measures include: using high-performance EMI filters at the power input; these filters not only suppress emissions but also attenuate externally injected interference. Common-mode inductors in the filters, such as the CMZ7060A series, and Y capacitors form a low-pass network and are critical components. Filters should be installed close to the power input, and their grounding terminals must be connected to the chassis with low impedance. For internal switching power supplies, enhance differential and common-mode filtering at their inputs. For signal ports, such as communication lines, use a combination of common-mode chokes and TVS protection devices at the interface. Common-mode chokes suppress common-mode interference currents, and TVS diodes clamp overvoltages. Using shielded cables and properly grounding the shielding layer prevents interference from coupling via radiation and conduction. In the internal PCB design, avoid directly mixing the ground lines of I/O circuits with those of sensitive digital circuits; isolation is typically achieved using ferrite beads or 0Ω resistors. On the software side, verification and retransmission mechanisms are added to data transmitted through interfered ports. By employing high-performance filters and protection devices from Audiotech, the conducted interference immunity of the frequency converter can be significantly improved.