Transformer leakage in LLC converters 

Thank you for the detailed explanation! Would it be possible to arrange a seminar focusing on the actual transformer design for a CLLLC converter? I find the aspect of designing the leakage inductance particularly challenging and would greatly appreciate a comprehensive discussion on this topic.

Thank You very much for this video. I also watched the other two videos and at the last now, i'm convinced, that You are right. Problem being, that i don't understand it, and i hope, You can give me a hint, where i'm wrong in my understanding: For this i want to look at an LLC circuit, using the T equivalent circuit, with one stray inductance on each side and an ideal tranformer, with a ratio of 1:1. Actually i don't want to look inside the transformer, because You already showed that even an external inductance on on side will not make a diffence, if compared from primary or secondary side. So, for this case, stray inductance shall be either an external inductor or stray inductance of the connections of the transformer, in any case, it is totally clear to which side it belongs. Now, talking about LLC, we have two important resonances, first is Cres with Lstray and second is Cres with Lstray+Lmagnetization. (simplified) I want to look at the second resonance frequency (which actually is the lower one). Let's now look at short circuit and open circuit. With the T-equivalent circuit, L would be Lstray,primary+(Lmagnetization||Lstray,secondary) for short ciruit on secondary side. With the L-equivalten circuit (all stray inductance on primary side), L would be Lstray, which is similar to Lstray,primary+Lstray,secondary, but the influence of Lmagnetization is missing, thus the resonance frequency (with Cres) would not be the same between L- and T-equivalent circuit. Now lets look at open circuit on secundary side: With the T-equivalent circuit, L would be Lstray,primary+Lmagnetization With the L-equivalten circuit, L would be Lstray+Lmagnetization, which is a higher inductance value, because Lstray>Lstray,primary. Again, the resonance frequency wouldn't be the same between L- and T-equivalent circuit. You are working with the mutual inductance, is it totally similar to the magnetization inductance? Or is it perhapps changing slightly btw. L- and T-equivalent ciruit, to compensate the above shown discrepancy? Let me ask the question differently: If i add an external inductor as a stray inductance, you still can explain this ciruit with an L- or T-equivalent circuit, if you do all the math right, but the behavior of a LLC-circuit will differ between putting the external inductor on primary side or secondary side, right?

very interesting presentation ! Thanks professor.

Excellent professor! Thank you!

Thanks man i need to learn it

Thanks professor 👌🙏

The equivalence between the L and T models are true only if magnetizing inductance is high enough so Lm//Llk(p,s)=Llk(p,s), i.e. Lm can be neglected. If Lm is low, then the most accurate model is the T one....

It is easy to believe that all of the representations can be equivalent when all of the elements are linear. In fact any n port linear network can have many related internal models for which the external network parameters are identical. What happens when the transformer elements are non-linear like core hysteresis or saturation? p.s. This was a very interesting series. Thank you

Sir why did you use pulse waveform top of the AC analysis??

5:20 Would it be possible for the very large inductance value to cause numerical errors in LTSpice? Clearly the simulation shows this to be a non-issue but I'm wondering how far one can go with such values.

👍🙏❤️