Design of Resonant LLC converters by scaled cloning

This presentation explains how to scale a given “good” design of resonant LLC converters so it will meet the required specifications in terms of power level, input or output voltage or switching frequency.

[perrykleez]

very informative, analytically practical & useful presentation...thank you SBY!

[chanh-tintruong]

Sir, in case the out voltage is changed 8:17, when the value of the load resistor will be changed to the new value. Thus the quality factor will be changed to the new value as well. Therefore, the characteristics of a circuit will be different. In this case, I think we need to keep constant Q by changing the L, and to keep the switching frequency, thus the value of the capacitor has to be changed.

[esijal]

Thanks for this helpful lecture, dear professor could you please give me a hint for the appropriate modifications in the controllers of LLC, specifically kp and ki, when we modify the parameters to the new values?

[RamPrakash-owwy]

Thank you, Sir, really appreciate your work.

[karastom]

Hi Dr Sam, in case of changing the input voltage, the turn ratio n will change also, you do not mention it in the lecture.

[rajeswariraje]

Is also called interleaved llc resonant converter.

[alchemy]

LLC ( limited liability Company) Resonant converters. I think it means that the manufacture company's owners have limited liability in case any defects cause harm and the like. I have to look in to that.

[audiokees]

I am busy with a LLC but it needs to go from 10mA (open output) to max 15 amps, I do loose the regulation and it go to max voltage of 75 volts, it is 65 normally regulated. when I draw 5 amps it does regulate fine, everything in simulation not real live yet, . Thanks

[rajeswariraje]

How many modes of operation in this circuit please explain it individually with wave form

[goutammaji]

Sir, one correction in video, quality factor Q formula has taken as R/wL but that supposed to be inverse of it i.e. wL/R.

[rajeswariraje]

Sir, I have another question what is the input for mosfet d. C or a. C then output. Thank u sir.

[scienceinnovativebrain]

Sir how to choose Ls and Cs for full bridge my transformer lm fixed 0.4mH np/ns =8/57 switchinf frequency 37khz.

[oropeiro]

can we just ignore the parasitic elements of the cirquit, (i mean the mosfet small parasitic capacitances, of the fuul bridge, and the transformer parasitic elements lm and llk), and solve the equivalent ?is this practical, for simple analysis? thank you..

[Azagro]

Thank you very much for doing my request! I see that you use a n:1 (n>1?) transformer, meaning it's in step down mode for the most part? Does this also go for n < 1? Or do you use a LCC converter in that case? Why?

[karastom]

Thanks so much Dr Sam, really very helpful.
Can I have multiple outputs with good regulation by using LLC

[GeraldTrost]

.
great, many thanks!

this is definately useful!

can you please explain what I need to consider -

- if I move to a different ferrit material in L1 and L2
- if I move to a larger Transformer with the same ratio

many thanks

Gerald Trost

[rajeswariraje]

Hi, sir what is resonant condition how we achieve it Sir I need a complete explanation please

[mohamedarrach]

Hi Dr Sam, First of all, thanks for your amazing efforts. But, I would like to know, the difference between the LLC and LCC in this topology. thanks in advance.

[AmitKumar-zbli]

Hi Dr Sam. I don't think this work below resonant operation. That FHA analysis is approx. This only cover above resonant operation in lagging power mode. Also this is not true at low load. We have different modes at low load or light load. Time domain analysis is needed to model it correctly.

[karastom]

Hi Dr Sam, I am trying to design 500W with 480Vin ac and output is 40Vdc, do you think it is ok if I let Fr to be 500Khz, is this frequency too much for the MOSFET ? I need to minimize my magnetics.