How to Use PLECS Simulation Model for Wolfspeed Power Modules?

Mahmoodreza93

Hello,

I am working on simulating Wolfspeed power modules in PLECS (especially CAB7R5A23GM4T one) and have a few questions regarding the correct setup, specifically for half-bridge modules.

Using Discrete FETs and Diodes with the Module XML File:

1- If I want to place two half-bridge modules on one heatsink, should I:
1.1: Use four discrete FETs, each with a parallel diode, and then assign the module .xml file to each discrete component?
1.2: Place one heatsink covering all components and use one heatsink resistor with a capacitor, then connect it to an ambient temperature voltage source (Tamb)?
1.3: Or should I instead:
Use four separate heatsinks, each for an individual FET and diode, and assign four separate heatsink resistors for each of them before running the simulation?
2- Alternative Approach Using PLECS Library Components:

Would it be more appropriate to take a half-bridge model from the PLECS library and then apply the Wolfspeed half-bridge simulation model to it?
3- Availability of Tutorial Videos:

Are there any official or recommended videos explaining how to correctly use Wolfspeed’s PLECS simulation models for power modules?
I appreciate any guidance on the best approach to set up the simulation correctly.

Thank you!

Forum_Moderator

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

BlakeNelson

Hi Mahmoodreza93,

For your first question, there are multiple correct approaches. I typically do not have a thermal capacitance value for the heatsink and arrange our models in this way:

I then define Rth,cf in terms of each switch position. This is an accurate approach for steady state, but less accurate if you are concerned about transient thermals. If you have a model of your heatsink, you could use this approach instead:

You can define a thermal capacitance for the heatsink and the thermal impedance between case and ambient using the resistor. Both are perfectly reasonable approaches, the difference usually comes down to how much information you have on your cooling system.

For you second question, I do not typically use the built in half bridge model when I am interested in solving for the module temperature or losses. The half bridge model does have some interesting capabilities however: you can use the averaged version to increase the speed of electrical simulations. This can be quite helpful in control design, especially if your system dynamics are slow.

For the third question, I'd direct you to the resources Plexim provides.
They have great tutorials that include example files: https://www.plexim.com/support/tutorials
As well as video content: https://www.plexim.com/support/videos

I think these are great resources to help you get started.

Let me know if I can help with anything else!

Blake