How can the equipotential bonding of the PCS in an energy storage system suppress common-mode current?

Equipotential bonding in a PCS system involves interconnecting all conductive parts within the cabinet (such as the chassis, shielding, filter grounding, and equipment metal casing) with low-impedance conductors, bringing them to approximately equal electrical potentials. This effectively suppresses common-mode currents:

1. Eliminates potential differences: Reduces the potential difference between different metal components caused by noise currents, thereby weakening the source driving common-mode currents.

2. Provides a legitimate return path: Provides a low-impedance metal return path for high-frequency common-mode noise currents, allowing them to flow locally within the cabinet rather than radiating out through external cables or space.

3. Coordinates with filters: Equipotential bonding ensures that the grounding terminal of filters (especially Y capacitors) has a stable reference point, allowing common-mode noise to be effectively bypassed to the chassis. Implementation requires the use of short, wide copper braided tape or copper busbars for multi-point interconnection.