How to isolate the communication ground and power ground of a frequency converter

Isolating the communication interface ground and power ground of the inverter is to prevent high-noise currents in the power circuit from contaminating sensitive communication circuits and ensuring stable communication. Isolation methods include: physical isolation, where the ground plane of the communication interface circuit is separated from the power ground plane by a copper-free area during PCB layout; and electrical isolation, using isolated communication chips, such as isolated RS485 or isolated CAN transceivers, to completely disconnect the ground connections on both sides through optocouplers, magnetic couplings, or capacitor isolation technologies. If isolation chips are not used, specific devices must be used to connect the separated ground planes to provide bypass paths for electrostatic discharge or high-frequency noise, while blocking low-frequency noise.

Commonly used connection devices include: ferrite beads, used for single-point connections, providing some isolation for high frequencies; and safety Y capacitors, such as 1nF Y2 capacitors, providing a path for high-frequency noise to the chassis ground. In terms of layout, isolation devices should be placed at the connection bridge position of the separated ground planes, and the communication interface circuit should be kept away from the power circuit. The shielding layer of the communication cable should be connected to the chassis ground at the inverter end, not the communication signal ground. By employing a reasonable isolation design and selecting the isolation communication solutions and connection devices from Yinte Electronics, the anti-interference capability of the communication interface can be effectively improved.