PLECS Model request for CAS325M12HM2

Luowei

Hi Wolfspeed, I want to ask for the PLECS model of CAS325M12HM2. I am using CAS325M12HM2 for a inverter and designing a new gate driver function for SiC. Now I am collecting the energy losses result of CAS325M12HM2 and hope to verify the results with PLECS model. Please let me know if you need more information and looking forward to your reply. Thanks.

Forum_Moderator

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

BlakeNelson

CAS325M12HM2.xml

CAS325M12HM2_schottkydiode.xml

Hi Luowei,

Sorry for the delay, I have put together some CAS325M12HM2 PLECS models for you.

I would recommend avoiding obsolete products such as the CAS325M12HM2 for new designs. I would likely recommend the CAS480M12HM3 for your application.

Let me know if you have any other questions!

Blake

Luowei

Thanks for the sharing, Blake.

I will use CAS480M12HM3 for new design in the future.

Luowei

Hi Blake,

I have two questions about the PLECS models of CAS325M12HM2 and CAS480M12HM3.

1) The PLECS model is for a whole half bridge module (top and bottom switches) or single switch? For example, when I have a three phase inverter (3 SiC module or 6 SiC switches), should I use three CAS480M12HM3 to generate the switching loss/conduction loss in the system, or use six CAS480M12HM3 to generate the losses.

2) I tried to use the CAS325M12HM2 in the PLECS and compared the loss in the model with the figures.17 and 18 in its datasheet. I found there are some deviations on the Eon when Iout<100A (compared to fig.18), what is your consideration when Iout is low (<100A) and how you decide the Eon when Iout is very small like 5A? Also, when I use the high Rg(ext) to calculate the Eon/Eoff, there are big change when Vdc is 800V, have you considered this big change before?

Looking forward to your feedback and please let me know if you need further information.

Thanks,

Luowei

BlakeNelson

Hi Luowei,

1) You will "apply" the xml model to each MOSFET model, i.e. one per switch position. To actually have PLECS solve for the thermal values, you will need a heatsink (and a path to thermal ground). You can find out more details in this tutorial: https://www.plexim.com/sites/default/files/tutorials_categorized/plecs/thermal_domain.pdf. There are a number of excellent PLECS tutorials available to get you started with the software.

2) If you find any points in the PLECS model you wish to change, the model can be easily edited. There is some ongoing discussion on the best way to fit the energies at low amperage, so this might be an area where the model could be improved. For example, it is likely that switching losses are not zero at zero current. Knowing the losses at a more specific small value (5A, as you mention), becomes difficult without data. A best guess would require extrapolating out the datasheet curves.

For the Esw calculations, PLECS accounts for your voltage, current, temperature, and gate resistance. So the simulation should account for the switching losses at high Rg and 800V. Of course losses can get relatively high in these conditions.

Let me know if you have any additional questions!

Blake

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.