How to connect the shield ground and power ground of the power FTU?

The connection between shielding ground and power ground must balance EMC and safety. A combination of capacitive coupling and direct connection is used. The high-frequency shielding ground is connected to the power ground via a 100nF/2kV ceramic capacitor, providing a high-frequency grounding path. The low-frequency shielding ground is directly connected via a 10Ω/2W resistor to limit low-frequency circulating current. The metal chassis is directly connected to the power ground with a 6mm² grounding wire. On the PCB, the shielding layer connection points use a metal shielding cover for 360-degree contact. This connection method achieves a shielding effectiveness greater than 40dB@1GHz, a grounding impedance less than 0.1Ω, and meets both IEC 60950-1 safety isolation requirements (3000VAC withstand voltage) and IEC 61000-4-5 surge test requirements.