How to reduce high-frequency impedance when grounding the PCS module of an energy storage system?

Reducing the high-frequency impedance of the grounding of power modules (such as IGBT modules and filter modules) within the PCS is crucial for controlling common-mode EMI. Measures include:

1. Using surface contact: Using a metal substrate (such as an aluminum substrate) or directly connecting the module's metal casing to the heatsink/casing via conductive pads over a large area, replacing traditional cable connections, significantly reducing inductance.

2. Multiple parallel low-inductance paths: If grounding wires must be used, multi-strand braided copper strips or flat copper bars should be used, connected with the shortest path, and multiple strips can be connected in parallel to distribute current and reduce inductance.

3. Grounding point selection: The grounding connection point should be selected near the source of the module's noise current, such as the pin location of the emitter or collector of the switching transistor.

4. Grounding network: A complete grounding copper plane should be provided under the module, and the module's grounding pins should be connected to this plane through an array of vias, forming a grid-like low-impedance structure.