Ringing effect related to CGD15HB62LP and CAS325M12HM2

Battur

Hello.

We have a 2-level 3-phase inverter with CAS325M12HM2 SiC, CGD15HB62LP Gate Driver, and CGD12HB00D Differential transceiver. We had a commutation noise sensitivity issue before with the above-mentioned gate driver, which doesn't send pulses to its outputs sometimes without triggering its fault and resulted in a ringing effect at the inverter output. So, the Wolfspeed engineers suggested changing the CB22 capacitor of the gate driver from 100pF to 10000pF (Murata Electronics GCM2195C1H103JA16D). It works, and we don't have any missing pulses at the gate driver output. However, the inverter output starts oscillating, as shown in the figures (line-to-line voltage). We didn't have this oscillation issue before. So, we would like to ask for the part number of the original CB22 capacitor and any suggestions for solving this oscillation issue. Also, our positive and negative busbars are overlapped.

Thank you for your time and support,

Battur (batkhisb@mcmaster.ca)

Forum_Moderator

Thank you for your post, it has been approved and we will respond as soon as possible.

PaulKanatzar

Hey Battur,

The BOM PN for CB22 is C0603C100J5GACTU. A suitable replacement would be a cap that is 0603, 10 pF (Or your new desired value), 50 V, and NP0.

With respect to the waveforms provided the disturbance appears to be the result of another phase switching. Do you suspect something different?

-Paul

TBhatia

Hi, I hope that this answered your question. I will close this discussion for now but if you have a follow up question, please "Start a New Discussion" and we would be glad to support you further.