Primary side control of output voltage and current of LLC converters

References:
Flyback primary side control
• Flyback primary side c...
H. Dong, X. Xie and D. Yu, "Primary-Side Regulation Scheme for LLC Resonant Converter With Improved Resonant Current Sampling Circuit," in IEEE Transactions on Power Electronics, vol. 36, no. 2, pp. 1242-1246, Feb. 2021, doi: 10.1109/TPEL.2020.3007987

[@ganopterygon]

Very interesting, this is similar to the current measurement in buck converter's inductors but has the extra rectification to estimate the output voltage, thank you!

[@sambenyaakov]

Not really, First, the Buck has no transformer, then the RC is not in parallel to an inductor but fed by a voltage source by an auxiliary winding thirdly the RC is not measuring the voltage across a parasitic ESR and therefore the selection of RC is not like in the case of the Buck

[@ganopterygon]

@@sambenyaakov I see, thank you very much for the detailed explanation

[@anoimo9013]

If I recall correctly, the magnetization current lays in quadrature with the primary voltage. If there could be some kind of arithmetic, may be taking the voltage across the resonant capacitor to estimate the phase of the quadrature current and subtract it from total primary current, then the output current could be inferred. There would be still the issue of leakage inductance proabably

[@sambenyaakov]

Thanks for comment. The resonant capacitor current IS the transformer current NOT just the magnetization current.

[@charizardrekt6083]

Hello Professor,
Thanks for posting these great videos.
At 9:08 shouldn't the equation be Ilm=VdRsCs/Lm instead of Ilm=VdLm/(RsCs)?

[@Ferraday]

Hello Professor,
Thanks for posting these great videos.
At 9:08 shouldn’t the equation be Ilm=VdRsCs/Lm instead of Ilm=VdLm/(RsCs)?

[@sambenyaakov]

Just checking your alertness 😉Yes, you are right. Sorry for the typo. I will put an errata on this in the description section.

[@yazmrt]

Does LLC converters are good choice for high voltage applications? Are LCC better for those kind of situations?

[@sambenyaakov]

How high?

[@richardandrews573]

How long have LLC converters been around? I have been wanting to experiment with two inductors in series. Much like an autotransformer but far less copper.

[@sambenyaakov]

LLC converters have been known for a long time. The introduction of IC controllers about 10-15 years ago helped to make the LLC very popular.

[@tamaseduard5145]

👍🙏❤️

[@sambenyaakov]

Thanks

[@Cydget]

Cool! Now how well does this work with real world components

[@sambenyaakov]

So you don't believe in simulation? Have you read the reference paper (and there are others) ? they are showing an experimental verification .

[@Cydget]

@@sambenyaakov I just thought that there might be some non ideal characteristics that might throw the results off a bit. I didnt realize they already tested it in the paper

[@sambenyaakov]

@@Cydget 👍