AC analysis tool prematurely terminating

Question

Hi all, 

I am pretty new to PLECS. I am trying to simulate the bode plot for a converter and I have introduced a perturbation in the duty and am reading the output voltage perturbation. I have already gone through the example for the buck converter provided in the examples before doing this. 

The simulation ends prematurely and plots the frequency response for a very short frequency range. It is unclear as to why this is happening. I asked it to plot the response from 100-100KHz and the following settings were applied:

Frequency Range: [100 100e+3]
Amplitude: 1e-3
Number of points: 150 <-- Is this too high?
Termination Tolerance: 1e-3 <-- I don't know what this is doing
Max Number of Iterations: 400 <-- Is this too high? I chose this arbitrarily
Rel. Perturbation for Jacobian: 1e-4 <-- No idea what this is..

I have attached the model for your reference. Any help would be greatly appreciated. 

Thank you very much!

Answer 1

Hello,

The first thing I noticed is that your model in its current form does not run do to an error message "cyclic behavior during switching". To better understand what this means, I recommend you see our website post on the topic: https://www.plexim.com/support/solutions/146. I was able to get your model running simply by increasing the "Diode turn-on threshold" solver setting from 0 to 1e-3. The small-signal analysis tools should then be able to converge. Note that for your model, you might consider the Impulse Response Analysis tool for a much faster result. I attached a plot capture below showing the results I saw when using this. Regarding the settings you emboldened above, did you review our documentation about what they do? I hope this helps!

Regards,

Kris