How to connect the inverter's shield ground and power ground?

Connecting the inverter's shield ground and power ground requires providing an effective noise discharge path for the shielding layer while avoiding interference. Shield ground typically refers to the chassis, cable shielding, or shielding enclosure; power ground is the high-current return path for the main circuit. Connection strategies depend on safety standards and EMC requirements. For protective grounding devices, the chassis must be reliably grounded. Power ground is typically connected to the chassis through a low-impedance point (e.g., the negative terminal of the DC bus or the grounding terminal of a filter capacitor). This connection point should be close to the noise source (e.g., IGBT) to provide the shortest possible discharge path for high-frequency noise.

Cable shielding should be 360-degree overlapped with the chassis at the inverter end via connector housings or shielding clips. For internal local shielding enclosures, multiple connections to the power ground plane or chassis are also necessary. In some designs, power ground and shield ground are connected via a ferrite bead or safety Y-capacitor to isolate low frequencies while maintaining high-frequency connectivity. The key principle is to provide a low-impedance, short-path discharge path for high-frequency noise currents to the chassis ground. The quality and quantity of connection points directly affect shielding effectiveness and EMI levels. Etymotic's shielded connectors and grounding assemblies ensure a reliable, low-impedance connection between the shield ground and power ground.