Mutual inductance versus transformer: the power electronics perspective 

Thank-you for sharing your experience and knowledge.

Another very interesting video. Thank you!

Great video Prof. Sam, thank you!

So educative may God reward you sir

Thanks for the great video.

Thank you for another excellent presentation . Since this is an educational video, I would like to point out a small discrepancy at 20:50 . The measured leakage inductance is in series with the primary , rather than in parallel .

thanks greatly for sharing very helpful.

Great presentation!

Thank you so much!

Thank you much for the explanation. Anyhow I have still some questions left, maybe you find time to answer: At 08:55 where in the drawing is L2 * k ? Is the winding missing? At 09:42 where does L1' come from (upper left image) ? The slide before it was just L1 and what is L2' in the formula? At 12:24 the formula for M: Is L1 seen from primary side and L2 from secondary side or both from one side?

Sir can you please make a video on a Planar Transformer designing parameters and also how to calculate the different losses in the Planar Transformer. Explanation of the Planar Cores would be also nice if possible. You are really good in it and i think Planar Technology in the market so, it will be interesting for all.

Thank you very much. It is really very helpful. I just have a question please. Beside these two mentioned models, there are also T-model and PI-model for the mutual inductance. My question is: Are all these models are theoretically equivalent or each one present some approximations?

Many thanks for this video. It is well explained and very educational. I have a question about the "transformer model" that Engineers like to deal with. The complete model (without series and parallel resistors) should show the magnetizing inductance only at the primary, i.e. Lm=L1*k. Am I right? At 9:08 at the secondary side there is L2*k, but I guess it is only present if we look for transformer behavior from the secondary, without L1*k. Moreover, the total leakage (seen for example on primary side as a series inductor) can be computed only assuming that the magnetizing current is negligible. In fact reflecting L2(1-k) results in an inductor of value L2(1-k)/(n^2) placed after Lm, in series with the ideal transformer. If the previous assumption is true, then the total leakage seen at the primary side is 2*L1*(1-k). Is this correct? Many thanks for your attention and your time! Best regards, Alessio

Thanks for this good vidéo. BUt i have a question, in the last Slide, the minding capacitance, what is the L, L2 ?

Sir, In a transformer, all physical parameters are fix. In primary side we connect to a fix AC voltage, say 220V AC. In this case, let say that it is stepped down to 12V AC. First: How do we derive the flowing current in a primary transformer so we may know the current in the secondary side? Second: As we know, load we connect to secondary side could be vary. How the secondary side handle its current go to the load? Or, is its output current a fix amount, regardless of the load we connect? Because once I heard said that the primary current is determined by the load connected to the secondary, not by the physical parameter like the inductance, core, and so on. Mean, if the load we connect to the secondary side will only draw a small amount of current, then the primary side will deliver a small amount of current, vice versa as long as the pulled current in secondary side not exceed the maximum current primary could deliver.

Nice video! But, sir, how to calculate L1 and L2? Suppose in dual active bridge converter, Leakage, turns ratio, power, Primary and Secondary voltage, switching frequency known. Then how to calculate L1 and L2, so that I can run the simulation. I am stucked at it

I have a question about the formula for K on slide 4... why doesn't phi_2 appear in the formula for K? Are there two different K's depending on your perspective? Is there a formula for K which is symmetric in phi_1 and phi_2? Or is phi_1 always the same as phi_2?

Hi Shmuel, I just want to mention the SPICE model of transformer that allows connecting a voltage source to both of the sides and comprises 4 controlled sources: K. Hatch, "Spice Model For An Ideal Transformer Allows Bi-directional Operation," 2009 page 51 here electronicdesign.com/site-files/electronicdesign.com/files/archive/electronicdesign.com/cluster/docs/products/29/17/ED090611.pdf

Sir, can you please explain the creepage and clearance constraints in Planar Transformer Designing.

thanks you very much. i just want to ask how to use transformer as inductor?

Sir, I have big difficulties finding explanation about the differences betweeen coupled inductors and transformers,do you have a video or an explanation on that subject? Because I am studying flyback converters, and some people say it is a coupled inductor that is used and not a transformer,others says the contrary...

8:26 Isn't the leakage inductance L_leak = (1-k^2)*L instead of L_leak=(1-k)*L ? v1 = s*L1*i1 - s*M*i2 v2 = s*M*i1 - s*L2*i2 = 0 (secondary shorted to measure leakage inductance) i2,sc = M*i1/L2 v1 = s*L1*i1 - s*M^2*i1/L2 substitute in M^2 = k^2*L1*L2 v1 = s*L1*i1 - s*(k^2*L1)*i1 = s*L1*(1-k^2)*i1 so the primary leakage inductance (secondary shorted) is L_leak = L1*(1-k^2).

What is the air core reactance of Transformer

@3:59 its not L1 is not self inductance, it should be actually magnetizing inductance.