Hi , all !
I encountered a confusing problem，as follows ：
Establish a schematic diagram as shown below，but convergence issues were encountered during simulation.
By chance, it was discovered that the SS port of sic mosfet M2 was grounded, and the simulation could be completed.
Why ?
If the SS port of the sic mosfet M2 is not grounded, is there an error in the schematic itself ?
Secondly, after the SS port of the sic mosfet M2 is grounded，the simulation results are as follows:
It's clearly wrong because when the sic mosfet M3 is turned off, the voltage of the VD is close to zero, and the correct result should be that the voltage of the VD is above 400V, in addition, the current flowing through R10 is also incorrect.
To verify the correctness of the circuit,NTHL040N120M3S model was used instead of NTH4L020N120SC1 model, the schematic and simulation results are as follows ：
NTHL040N120M3S model download website ： Case: 00451022 (site.com)
NTH4L020N120SC1 model download website： Case: 00503736 (site.com)
So, why is the simulation result obtained when using NTH4L020N120SC1 model incorrect? How can I solve it?