How to protect the PAC smart controller from EFT (Electrical Fast Pulse)?

To protect the PAC (Power Flow Controller) from EFT (Electrical Fast Burst) interference, filtering and shielding are required. At the power port, a common-mode inductor (CMZ7060A-701T) and X/Y capacitors form a filter, with a TVS (5.0SMDJ36CA) connected in parallel to absorb transients. At the signal port, a ferrite bead (PBZ1608A-102Z0T) is connected in series with a TVS (SMBJ6.5CA) in parallel. All port filtering components are placed close to the interface. The PCB uses a multi-layer board with a complete ground plane. Shielded cables are used, with both ends of the shield grounded. The software employs a watchdog timer and error correction mechanisms.

During testing, IEC61000-4-4 Level 4 (4kV, 5kHz repetition frequency) pulses are applied to both the power and signal lines, and the system function is not lost. Through design, the PAC can withstand EFT interference with a bit error rate of less than 10^-6.