Mohammad,
Please see the attached model. There could be other underlying issues in the model, but the simulation can run after a few key changes:
The “N” and “P” electrical tags in your model were “global” basically shorting out the converter arms. I removed them as they weren’t necessary.Note the “sw_config” variable in the model initialization commands. Here you can use between two switch models 1) Seperate “IGBT” and “Diode” components from the PLECS library and 2) One “IGBT with Diode” component. Having the components integrated is a huge reduction in the number of switching combinations. The model runs much faster in the second configuration.If sw_config=1 (separate components) note that non-zero forward voltages exacerbate the error message. They are set to zero in the attached model.And some aesthetic changes:
Vectorized the MMC arms so the number of cells is configurable.Improved modulation scheme. Using the “relay” component with “+/-eps” hysterisis could be problematic and lead to cyclic switching, but wasn’t the root cause here.
DSM5_BL.zip (37.7 KB)