Hi Jerry,
There is a “Variable Phase PWM” block in the PLECS library. You can use that generate the PWM signals. If you place a “Probe” component in your schematic and then drag-and-drop the PWM block onto the probe (or into the probe window) then you can access the carrier signals.
There are other approaches that are less straightforward. You can use the block from the TI C2000 TSP but it requires additional configuration steps (you need to place it within a Code Generation Subsystem and configure the target for a TI C2000 processor). One cannot access the carrier signals directly with this block due to its implementation.
You can also generate the carrier yourself directly using the approaches outlined in this forum post.
Regards,
Bryan