How to isolate the communication ground and power ground of EPS?

In EPS (Electrical Power Module), the "communication ground" of communication circuits (such as RS485, CAN, and Ethernet) needs to be isolated from the noisy "power ground" to prevent power ground noise from interfering with communication through ground coupling. Isolation methods include:

1. Using isolated communication devices: Employing isolated communication transceiver modules (such as isolated RS485 or isolated CAN transceivers). These modules achieve signal isolation internally through optocouplers or magnetic couplers and provide independent power to the isolated side.

2. Dividing the ground plane: On the PCB, dividing the area of communication devices and related circuits from the power ground area into separate ground planes.

3. Single-point connection or ferrite bead connection: Connecting the communication ground plane and the power ground plane through a single point (usually chosen near the "ground" pin of the isolated communication module) or through a ferrite bead to block high-frequency noise while maintaining approximately equal DC potential.

4. Independent interface grounding: The shielding layer of the communication interface should be connected to the communication ground reference point, not the power ground. Isolation is an effective means of ensuring communication reliability.