Electronics tutorial - Inductor saturation

#96 #electronics #inductor
In this video I look at magnetic saturation - what it is, how it can influence the performance of a power inductor or a filtering element, and more importantly, just how much information can you actually get about this from a datasheet.
Datasheet used:
ro.mouser.com/datasheet/2/445...
ro.mouser.com/datasheet/2/427...
ro.mouser.com/datasheet/2/281...
ro.mouser.com/datasheet/2/281...
www.tdk-electronics.tdk.com/d...
Special Thanks to all my supporters on Patreon! Especially @afiskon, Xegomen and Ralf B.!
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[@jfalbo1]

Keep up the good work educating others on electronics. Since being sick I've been scanning youtube much more than normal and came across your videos. I've been a design engineer for a few decades now and I really, really like your teaching approach - teach, show on scope, look at data sheet...Well done!

[@FesZElectronics]

Thank you for the kind words! Get better soon!

[@gabrielzambo8198]

Great video! I like the fact that you always explain the datasheets. THANKS!

[@EJEuth]

‘FesZ’ another great lecture. Some professionals know the Fundaments and manage well technology; others have didacticism to teach and share the knowledge, but have gaps to link theory and practice. Lucky for us, you very good in all those sides! If you already are not a teacher or instructor, you should think to become one. Greeting from Brazil to Romênia and please continue this great work.

[@user-ys7nj9pz7w]

I wish I could have viewed these short tutorials when I was doing my degree. I hope education professionals direct their students to view these as a supplement to their studies. Keep up the great work.

[@ScattyPictures]

Really good explanation! You helped me learn a lot. What you do really is important for humanity, learning is important.

[@fpgamachine]

Excellent info, thanks!

[@pabloezequieldominguez6954]

Excellent, thank you very much

[@chrisfuller1268]

Great video!

[@happydog6093]

Thank you

[@p_mouse8676]

Excellent video! 👍🏻 You forgot one other important parameter that can cause saturation and that is heat. So when the core is heated up (even by some hot external component) the inductor will saturate more. But this will also happens with more current through the inductor itself. So in the end you have a double penalty. The current causes saturation as well as current heating up the wire (inductor). Unfortunately this is rarely shown in datasheets and as far as I know Sumida is the only manufacturer that gives the inductance vs current curve by two different temperatures (20 and 150 degrees C)

[@FesZElectronics]

I didn't want to go into this part because temperature influence is a more complex behavior; I've noticed that most ferrite materials in the TDK catalog (www.tdk-electronics.tdk.com/download/519704/069c210d0363d7b4682d9ff22c2ba503/ferrites-and-accessories-db-130501.pdf) have increasing permeability with temperature - example material N48 page 70. Permeability is increasing with temperature up to 160C and then sharply drops. So its a bit of a longer discussion to show both the permeability increase and decrease with temp.

[@p_mouse8676]

@@FesZElectronics Correct. I personally would briefly just mentioned it. In the end it can be a factor to what size inductor one has to choose. Especially with high power/high current applications. But heat can definitely also ruin your day with small inductors.

[@anshaggarwal2060]

Hey, thanks for this video and for the other videos. I have a question about a datasheet of an inductor core that I picked up, it has only Bsaturation (magnetic flux density at the saturation current), could you describe how one can calculate the saturation current out of it? Thanks in advance

[@hedleyfurio]

If possible could you simulate a common mode choke as found in a lan transformer . This caused months of problems when using on POE . I think common mode choke got saturated so as cable got longer line noise went up . Workaround was to flip transformer so the common mode choke was on the phy side vs the line side . Better results but I don’t really understand what was happening .

[@dalenassar9152]

Hello, This is one of the most valuable illustrations I have seen on inductance. Where you illustrated how a permanent magnet can influence the the inductance was especially interesting. I HAVE A QUESTION ABOUT THIS: could you actually DECREASE the flux in the core by an arrangement of permanent magnets? ALSO: If you are using an AC input with no offset current, and since the current is increasing and decreasing at the same rate, won't the flux also flip with the current? If so, then how does the core saturate if the flux is growing and decaying at the same rate--does saturation (in this case) just grow, go back to zero then 're-grow' in the opposite direction. My only guess would be that in this case the saturation occurs at the peaks of each half-cycle??

[@ikbendusan]

can you do a video about estimating core losses in ltspice?

[@jamest.5001]

Would it add performance to a Motor/Generator , to use a field core from sheets of silicon steel. With holes taking away approximately 30% -40% up to 65%+/- of the steel away to use it as a support material for a ferrite core, possibly by adding the ferrite as round bars, especially if the motor uses a vfd or is a bldc /electronically commutated motor. Also a Generator or pma can spin at high speed, producing a high frequency AC current. Would the ferrite hybrid core offer any efficiency gains? Being ferrite is too fragile to reliably be used in motors, especially those where the cores are rotors, or part of the mounting frame.

[@lowcurrent]

Are there more informations about the power amplifier?

[@neteagle2k9]

Hi very interressing video, thanks. Can you show the inside of your DIY signal generator ?

[@FesZElectronics]

Hello! Well, the signal generator is an Analog Discovery 2; the power amplifier is the only "DIY" part

[@rZERO_game]

Sir , I have understood the different parameter which influence the behaviour of inductor. Now say some one has EE core need to know its parameter such that in which frequency core generate or maintain its higest inductance so that we can fix our smps frequency first, then how much temp it holds its inductance value , how to measure saturation flux density, etc.Say i have a core but dont have any data sheet ,now i have to find out its property for implimenting core in SMPS.

[@kacperbardecki3671]

I wonder if this matters for instantaneous current. For example, if I have 0VDC bias, but 28Arms, and inductor is rated for 30A but with Isat being 15A, how will my circuit be affected (at 100kHz)? Awfully specific, question, I know.

[@FesZElectronics]

28Arms is about 39Apk; most likely the inductor will end up loosing a lot of energy and heating up since its pushed way past the 15A saturation point. Usually you find 2 ratings - one for heating (current at which the inductor heats up by ~30C - exact definition is in each datasheet) and the other for saturation (current at which inductance drops by ~30% - again exact definition is written in the datasheet); if you are using the inductor as a basic filter, the heating current can be used since you want to absorb energy anyway; but if you are using it in a switching converter, there you want to minimize losses you want to keep it below Isat

[@shanefrank3281]

Very helpful video. But I have a couple of questions. For the 100mA offset case, I calculated 35 ohms instead of 32 ohms. I know it is close, but just wanted to make sure I understood things. (50x (750/440) - 50). Also, you are using the BLM21PG221SN1and say the datasheet has the impedance listed at 80R at 10Mhz, but when I look up the data sheet it is 220 ohms at 100MHz. Is that correct? Thanks again!

[@FesZElectronics]

Hello Shane! You are right, for the calculation its 35R, I made a mistake when copying the value. For the second part, the datasheet does say 220R at 100MHz, but you also get a graph showing how impedance varies over a wider range. Impedance is not a constant, only at 100MHz do you get 220R at other frequencies its different, and since I was interested in 10MHz, I extracted the 80R value (see: www.murata.com/en-eu/products/productdetail?partno=BLM21PG221SN1%23 there is an impedance graph from 1MHz to 3GHz)

[@shanefrank3281]

@@FesZElectronics Thanks for the response and the datasheet link. The one I had come across didn't have any graphs so that is why I was confused.

[@BjornV78]

6:14 So if you placed a small electromagnet nearby a inductor, you can satured the inductor galvanic ? Can this not be used on a SMPS to control the output ?

[@Telectronics]

You can blow up your SMPS with that method

[@Telectronics]

Nice old technology I didn´t know that it was used but what I was meaning If you overdo the saturation increase. The electromagnet in the video made the inductance near zero.

[@BjornV78]

@Joachim Shekelberg , i didn't know this technique of controlling a SMPS, but it was the first thing what came to my mind. My guess is, if the inductor get satured from a external source, that the inductor acts like a coil connected to pure DC and gets hots or burn out ?

[@BjornV78]

@Joachim Shekelberg , what i meant was, that a inductor in a SMPS normally deals with pulsating DC right before this pulsating DC gets to the little pulse transformer. And when the inductor gets satured with a electro magnet, the inductor acts like a coil where a pure DC voltage is connected to. Grtz from Belgium.

[@Telectronics]

@Joachim Shekelberg Yes you are right but your saturable reactor depends on the load to not blow up. If you try to push more current at the AC side you will burn the inductor out too. To be clear I mean in saturation mode If you are out of saturation(depends on your potentiometer) your current will be limited by reactance.

[@user-if4ee2ws9t]

hi, how to find big core saturation point, for example EE55 or EE65, small core is very easy but big core very tiring?

[@FesZElectronics]

If I am not mistaken, the saturation is dependent on the core material and the core volume - the core material should have its own dedicated datasheet, and the core geometry should also be available.

[@yakupemre1]

Hi man, your videos are great. I have only one question. Can I use paralel inductor for prevent saturation. Is this stution have a disadvantages?

[@FesZElectronics]

Well, you could use 2 inductors in parallel, to half the current, but that would also half the inductance (total value of inductors is calculated like for resistors); on the other hand, it should be easier to just use a bigger inductor; I mean, it should occupy less space and also be cheaper than using 2 or more inductors of smaller current rating.

[@ovidius2000]

​@@FesZElectronicsbiggerIronCoreMeansItCanStoreMoreMagnetismUntilReachesSaturation?

[@ClaudioGabrielCastillo-uq4hj]

Your channel is great..............but this video does not have subtitles

[@stevenbliss989]

Ever considered doing a DIY saturation tester?

[@FesZElectronics]

Not really... I don't have anything planned for that at the moment.

[@dalenassar9152]

One thing that they say in many videos is that "IF THE INDUCTOR REACHES SATURATION, THEN ALL INDUCTANCE VANISHES". Doesn't it actually fall to the value that it would have if it was 'air-core'?

[@FesZElectronics]

In most cases saturation isn't like a brick wall - before full inductance after 0; its a more incremental process, and of course this depends on the core type - some cores have a gradual inductance decrease (like metal powder core) others have it more abrupt (like ferrite); You are right, if you fully saturate the core, you still have some inductance left, it will never become zero, but I guess what others are trying to say is that saturated inductance is very small (more than 10-100x) compared to the initial value, so its like having nothing.

[@JohnDuthie]

Are inductors trying to reduce the magnetic field or the opposite? I still have a lot to learn.

[@FesZElectronics]

I'm not sure I follow. The inductor is the main generator of the magnetic field. The core just helps with the magnetic flux density.