Key EMC design considerations for wide bandgap devices in energy storage system PCS?

For PCS using wide bandgap devices such as SiC/GaN, due to their ultra-high switching speed, EMC design requires special attention to the following points:

1. Extremely low parasitic inductance layout: This is crucial. Techniques such as multilayer busbars and planar transformers must be used to reduce the parasitic inductance of the power circuit to the nanohenry level to suppress the large voltage overshoot caused by high di/dt.

2. High-frequency filtering capability: The noise spectrum extends to hundreds of MHz or even GHz, requiring the selection of common-mode inductors with high impedance in this frequency band (paying attention to their self-resonant frequency, SRF), and high-frequency decoupling using low-ESL ceramic capacitors.

3. Driver circuit optimization: The driver circuit requires extremely low inductance. Driver ICs are often integrated with or placed close to the power transistors, and gate resistors are finely optimized using dual-pulse testing to balance switching speed and ringing.

4. High-frequency shielding: The shielding of the cabinet and cables must effectively suppress higher-frequency radiation.

5. Near-field coupling control: Managing parasitic capacitance between devices and on the heatsink is critical, requiring the use of low-dielectric-constant insulating materials and optimized structure. The design challenges are greater, but the performance ceiling is also higher.