Dear plexim Team
PFC_einphasig_bidgless_bipolar_APFC_Regelstrecke_bestimmen.plecs (26.1 KB)
In the attached model i want to measure the controled system with the help of an AC sweep. In comparsion to the buck converter example this model has a AC voltage source. When i try to measure the current response (iL) i get a unrealistic solution (amplitudes and phase response with many peaks). Is it possible to measure the controled system H(s) = iL/D like this? What do i have to adapt in my model that it will work?
Thank you for editing this post.
Best regards,
Raphael Baumeler
Hi Raphael,
Small signal analysis conceptually requires operating around a linearized operating point. That is not the case in your model. You are operating at a constant duty cycle while the AC grid voltage changes. If we think of the ~iL/~D of a buck converter, it depends on D’ or 1-Vin/Vout so there isn’t really one transfer function for this system as you’ve implemented it.
A common approach for analyzing PFCs would be choose a DC operating point on the AC curve for the controller design. Another approach would be to implement a controller and reformulate the perturbation such that the perturbation represents a “more linearized” system. Christopher Basso has good reference material on this topic.
Regards,
Bryan
Hi Bryan,
Thanks for your reply. I understand that my model will not work. Can you show me how you would analyze this model with a DC operating point?
Where can i find the reference material from Christopher Basso? Do you have an example?
Thanks for your time and help.
Best regards,
Raphael
Hi Bryan,
Thanks for your reply. I’ve tried it with a DC Voltage Source and it works now.
Thanks for your help.
Best regards,
Raphael
Glad to hear you have things working. Regarding Basso’s work, I believe he had a recent tutorial at APEC on PFC simulation. He also has several books, but I’m not certain which one is most relevant to your immediate question.