The switching loss of the SiC MOSFET is displayed as 0 during the switching action

1

Hello, I am a new user of plecs. When using plecs thermal simulation, I have some problems in calculating the switching loss of probe module.

The first diagram is my circuit diagram, which is a 3L-ANPC circuit built by me (CAS480M12HM3 is used). The second diagram is the probe test result image of fet8. The top part of this diagram shows the voltage of fet8, and the fifth line shows the switching loss of fet8.

Why the fifth line shows switching loss only when the device switching operation is positive current? It also has switching action in the previous paragraph. Why is there no switching loss?

I have attached the simulation in the attachment

3L-ANPC.png
3L-ANPC.png1506×905 75.3 KB

FET8.jpg
FET8.jpg1938×919 194 KB

test.zip (23 KB)

2

Hello, if you “zoom in” in the Scope during these switching events when the AC current is in the negative half of its cycle, you will see the the device voltage is already at zero when the MOSFETs begin conducting, hence, no switching losses are generated.