How to ensure EMC compliance for inverter cabinet grounding?

Inverter cabinet grounding that meets EMC requirements must provide a low-impedance noise discharge path and a stable reference potential. Cabinet grounding is not only a safety requirement but also fundamental to EMC. The cabinet should have a dedicated grounding busbar (copper busbar) that is connected to the cabinet frame at multiple low-impedance points. The grounding terminals of the inverter, filters, and other auxiliary equipment should be connected to this grounding busbar using short, thick wires or copper busbars. Movable parts such as cabinet doors and side panels should be connected to the cabinet frame via braided grounding straps. The cabinet's own grounding busbar is ultimately connected to the building's grounding system via a conductor of sufficient cross-sectional area (such as yellow-green wire).

For high-frequency noise, the inductance of the grounding conductor is critical; therefore, connections should be as short as possible and flat conductors should be used. In environments with severe interference, adding a grounding copper plate at the bottom of the cabinet can be considered. All grounding connection points must have clean contact surfaces to ensure direct metal-to-metal contact, and toothed washers should be used to prevent loosening. The impedance of the grounding system should be checked regularly. A good cabinet grounding system can provide an effective discharge path for the common-mode noise generated by the frequency converter, prevent noise from radiating through the cable or affecting other equipment, and also improve the system's resistance to external interference.