Hello,
I keep getting this error and I don’t know what to do.
Here is the file bellow
buck.plecs (16.1 KB)
The error condition ‘Cyclic behavior during switching’ means that a switch receives an opening command and a closing command in the same time step, and so PLECS is unable to determine a conduction state. A diode, for instance, might turn on at one instant, because it measures a positive voltage, but after having turned on, the current through it is instantly negative, so it turns off again.
In some cases this can be numerical, and there are some tips on how to tweak the solver settings available. However, in other cases it may be due to the fundamental construction of the model where there is no valid solution.
I suspect in your model it is a fundamental issue with the converter you have constructed. I’m not familiar with the exact arrangement in your model. Perhaps there’s a paper or reference you’re basing this model on that you can share?
Your schematic doesn’t match this configuration - note the placement of C3 and D3 in your PLECS model.
Even with that correction your circuit still has a few fundamental issues. In particular when the FET turns off L2 and L3 must have equal currents, but they do not. I added an artificial R4 in parallel with L2 so the simulation completes, but you can see the voltage stress across the devices is destructive. The addition of R4 is to “bypass” the errors so the circuit will simulate and can be analyzed further, but the underlying issues remain.
It’s up to you to resolve the underlying issues in the circuit. I also made several other comments regarding the model including suspicious inductor parameterization and a state-source dependency issue.
buck_BL.plecs (26.8 KB)