I am unsure whether I should edit on my previous question or create a new one. Please give me your feedback on the proper way of doing it here.Back to the question, I have struggled for the past few days in creating a 2 output flyback converter. Ideally, the Vo1 and Vo2 should be 12V and 8V respectively. The ideal current flow was 5A for both windings(Desired Pout = 100W) but I can't seem to get the desired result. Images are found below. As I am not allowed to post more than 2 links, the voltages that I obtained was Vo1 = 18V, Vo2 = 12V. I have based on my calculations as provided by the kind hearted people around here. I have based my calculations based on AN4137 and some design calculations by micro rohm. In actual fact I would like to use the UC3844 as my controller IC but Im still negotiating with the people from PSIM to grant me access to it. Hence I base my switching device with a pre design available in PSIM. Some information that I think is needed, Transformer core based on EER40, Ae = 149mm^2, AL = 5200, Lm = 2.9mH, Leakage based on 10%, Vin range: 220 - 240V. Np min = 58.38. Fsw = 100kHz Sorry for the long post. I hope someone can guide me along. Thank you.

PS thanks for the upvote, I have uploaded the voltage output PS I have adjusted the flyback design

FLyback Design


Current Waveform

Voltage Waveform

  • 1
    \$\begingroup\$ Are those ammeters at the outputs? If so, you are shorting the outputs! Then how would you expect to get output? \$\endgroup\$ – Rohat Kılıç Dec 5 '16 at 16:14
  • \$\begingroup\$ If you lower the duty cycle from where you have it (p[lease state) a little bit, do voltages drop to values that you expect? \$\endgroup\$ – Andy aka Dec 5 '16 at 16:16
  • \$\begingroup\$ Here is an upvote, so you can post more links when required. +1 for persistence. \$\endgroup\$ – Marla Dec 5 '16 at 16:17
  • \$\begingroup\$ @ Rohat, I tried to connect the ammeter without the shorting the output, but I guess PSIM found it as an error. Ill try again \$\endgroup\$ – Iskandar Dec 5 '16 at 21:50
  • \$\begingroup\$ @Andy aka, the duty max would be 0.48, the typical max for IC UC3844, hence I used that value for my calculations, should I lower it ? \$\endgroup\$ – Iskandar Dec 5 '16 at 21:51

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Browse other questions tagged or ask your own question.