The presentation describes an intuitive procedure for designing high frequency air gaped power inductors and distributed gap inductors. Error correction: In slide 3-4 H=nI/l (l is missing)
Thanks to your videos I now have a lot less interference going back into the mains when I use my monster ZVS driver, for me it's now easier to know where the signals go and how I can isolate different frequencies, especially the high frequencies with high power from going back to the the line voltage or mains.
Thank you for the correction. You have a keen eye. Sorry for the slip up. I could have said that I did it on purpose to see who would catch. But I did not :-)
Hi, I think I saw a comment fofyour regarding an equation in minute 20.06 of video (to divide by 2?). I can't locate the comment. Please rephrase as I do not understand the reason why you think that a correction is needed.
Thank you so much for the lecture professor! can you please tell why the number of turns and the Window area depends on the RMS current, while the cross sectional area depends on the peak current in 20:29
Rms determices the cross section of wire and area of wires and time n is the area you need in window which we what to fill. Ae is bound by the constraint Ipk L= n Ae Bmax
Prof. Ben-Yaakov, is there a core losses calculation part? Also, how come there is no copper losses equivalent? Combining the core size calculation with the copper losses (and possibly the core losses too) one could create a (probably) quite nice optimization problem.
Thanks. These are left for homework😊Given the Delta(B), the frequency, the magnetic materiel chosen, the diameter of the wire and the mean winding length the losses can be calculated.
Hi professor, thanks a lot for the lecture. Question here, how do we take into account an offset with delta B when looking into selecting an inductor? For example I got a simulation of the flux density in a power inductor, but apart from the carrier frequency expected variation, there is a notable offset due mains frequency. So do I take that into account or look only into the ripple caused by the high frequency?
It was a very informative video. Actually, I have been working on inductor design and after selecting a ferrite toroidal core (x1.5Ap required), I have observed that it is saturating due to very low Bsat (0.2T) of the core, I assume. After watching the video, I plan on introducing a small air gap in toroid ring core as I have a lot of area unutilized. Any thoughts on this?
@@sambenyaakov Thankyou. I had already found their site but everything seems to be in PDF form only now. But at least with your confirmation of it, I can ask them if its still around. Thanks.
Thanks for the video Prof! It was very enlightning. I have a question regarding distributed gap core. When you say the core has u= 125 does it mean that effective u is 125 or does it mean the effective mean is u0*125 (1.256e-6*125 = 0.157e-3)? Can you please clarify.
Yes, I saw that. It did not make sense because I did not see the "dot" in front of the "4". So it is actually 0.4*Pi*10^(-8) H/cm, which by the way I think you have a typo at 32:26
Thank you Professor for continuous sharing of inspirational ideas. By the way, I'm just curious, in 6:07, you define "H" as "H=nl". However, is "H" suppose to be H=nI/L, where H is the magnetising force in ampere-turns per meter (At/m)? .
Thanks Dr Sam, very good explanation In resonance circuit we have to pick inductor with high Q, is this means that inductance will be stable and not vary when Q is high? and how we can figure required value that we need it?
in power electronics we talk about series resistance and not Q High Q basically means low Rs. In power electronics some changes in inductance are tolerated because the systems usually works in closed loop.
@@sambenyaakov thanks Dr Sam But there are some materials that have high Q And resistance depending on wires , so Q related to materials not to wires? Is that right
@@karastom2304 Sure you are correct, core losses account. But still, in RF circuits of low power we worry about Q, in power electronics we talk about losses.
Hi Dr Sam, thanks so much , as usual you are amazing , your lectures are very helpful . i have question about the Ac ,i do not see in the equations the effect of frequency on Ac, like when frequency is high we should be able to use smaller Ac , and also what is the effect of the topology (forward, flyback,half bridge, full bridge on the Ac. Thanks so much Dr Sam
Hi Karas, This video is a very basic tutorial. Additonal issues are covered in the new ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-r-hK2OZp5D0.html
Hello Professor, again, amazing videos can't thank you enough for everything! I've recently become aware of the difference between small signal permeability and average permeability, where Uavg=B/H and Usmall_sig=dB/dH. I've always just used Uavg (Ur and/or Ue). I'm still figuring out which applications use which, but it seems generally we use Uavg within HF power inductor design. Is that correct? The reason I bring this up is that n=(L*Ipk)/(Ae*Bmax) is now a bit confusing to me notation-wise since when I think of Ipk I think of the DC component + half the ripple component. So, when using that formula shouldn't we just be using the peak average current, not including half of the ac component?
@@sambenyaakov Thanks, I have not read that before, it was a great read on permeabilities. I'm still not sure if the paper addresses my last question about the DC component + half the ripple. Or if it does, I clearly didn't pick it up :)
Hello professor, this was a very nice lecture but i can't seem to understand the RMS value at 23:30. First of all I have seen the comments below and i know that 1/T should be inside the square root, i suppose that the integral limits should be at a given period of time (0 to T for example) but i am not sure about the equivalent equation of inductor current (IL). I used LTSpice in order to simulate the situation on a buck converter during DCM and CCM operation but i can't seem to find the right value of RMS current through the inductor with calculations, the value differs completely from the calculated value of LTspice. Last thing i want to mention is that i have seen the generic corresponding formula of a periodic signal over time from Wikipedia (Definition - Equation 2), should the f(t) (corresponding inductor current - IL) be replaced with the typical equation of V = L*di/dt or something else? Thank you.
Sir, Why is it that the cores with discrete air gap have a sharp saturation, whereas powder iron cores with distributed air gap have a soft saturation? Can you please justify physically?
