High frequency Power Inductor Design: DC & AC

Detailed design steps for both AC and DC HF power Inductors is explained. The main objective of the video is to answer following two questions which had troubled me during my first inductor design.
Question1: which formula for number of turn????
N=√(L/AL) . or N=(L*Im)/(Bm*Ac)
Question2: Is air gap required in Inductor???
The above questions are answered in detail where two inductor design examples using ferrite and iron powder toroidal cores are illustrated to support the proposed methodology.
Link of contents: drive.google.c...

[@nathanwineera8716]

I believe that the statement at 12:48 in the video is incorrect in relation to equation (4). You state ..."if the reluctance of the core is higher then the core can saturate...". Shouldn't this be "...if the reluctance of the core is lower then the core can saturate..." instead? As at a lower reluctance the inductor operates with higher flux density B from (4).

[@congtuduong2040]

thanks sir so much, i'm really like this video.

[@riteshraj4038]

Thanks a lot sir, really helpful and cleared a huge number of doubts

[@rahulsejwar1462]

your efforts are so good. but My Question is this I want to make Air core Inductor for pulse generate, so how I will know L or I(current) and such as You choose 25 kHz or 0.2 by the table so How could we know frequency for design inductor? Please give advice? Urgent

[@gyanendrakumarsah2097]

We design inductor only if we have its specifications (like L, Im, Freq. etc.). In other word, these informations u have to get before proceeding with inductor design. In your case, u should follow some pulse generator design steps and need to get the required specification of Inductor. I am not an expert in designing pulse generator. For eg. while designing any power converter, we compute the required design parameters of passive components for given input and output conditions using design equations of the respective converter. And then we use the obtained parameters to choose or design the passive components. I guess, in pulse generator the frequency will be varying and hence it will be operating within a range (Fmin to Fmax). In that case, I recommend you to choose Bm for Fmax to be on safer side (this will make sure, the core will not get heated up while operating at maximum frequency but the size of core may increase dramatically). you may also choose some middle frequency depending upon how effective is your thermal management (this will help you to reduce the size of inductor). Note: Inductance and current rating of inductor need to get from the pulse generator design steps for given input and output constraints. Thank you for your question and let me know if any query you have regarding inductor design

[@rahulsejwar1462]

Ok

[@Muhammedali-yc8ev]

Thanks for this video Can you make another video about high frequency transformer

[@Pudersepp]

A question: when calculating Ap for: L=33 uH, freq=125 kHz, Imax=2.5 A, AC mode, Bmax=0.12 T, then Ap=((33*10^-6)*2.5^2)/(0.12*0.6*1.414*3*10^6), I get a riddiculously small number, Ap~10^-10 cm^4. By methods described here (using max AC power to derive the Ap, needed power is 300 W +): coefs.uncc.edu/mnoras/files/2013/03/Transformer-and-Inductor-Design-Handbook_Chapter_10.pdf I get around 0.31 cm^4, which would seem to make sense at least in the domain on order of magnitude. Why this discrepancy?

[@mankapowerelectronics364]

Hey, nice question. The unit of answer we get from formula (Ap=(L*Im^2)/(Kw*Kc*Bm*J)) is in m^4. To convert m^4 to cm^4 , we should multiply obtained answer by 10^8. The answers of ((33*10^-6)*2.5^2)/(0.12*0.6*1.414*3*10^6) is equal to 0.06752907433 cm^4. The input taken for designing inductor in coefs.uncc.edu/mnoras/files/2013/03/Transformer-and-Inductor-Design-Handbook_Chapter_10.pdf and the method discussed in this video are slightly different. In the former documentation, the inductor is designed based on its volt-amp rating and its operating frequency where inductance is computed at the end (Ap, N, and inductance may vary depending upon VA and Freq requirement) but in this method the inductance value and its current rating are already known (remember these are computed during designing any power circuit) and hence we design inductor to achieve required electrical and thermal conditions. In other word, these two methods uses different inputs requirements and hence different design steps but both can be used to get required inductor design with minimal discrepancy. I hope this might have answered ur questions. Please feel free to raise any concern doubt, will be glad to help if I can.

[@Pudersepp]

Thank you!

[@tapansarkar3495]

Sir please give a vedio of high frequency transformer design.

[@jayswaltaksh8665]

My Area product is 65.14 cm^4 can you please find out area of core and window for me and for which core I should go..

[@shashankshrivastava6456]

Please make video for core loss calculation for torridal core and it's temp rise

[@titeman9374]

Your result in wire area with enamel is very very wrong because [(3.142*1.709^2)/4)] 1s 2.29mm^2

[@mankapowerelectronics364]

Hey, I have mentioned result in cm^2. 2.29mm^2=0.0229cm^2.

[@lazeeemanwithlazeeetricks3947]

Thank you Sir for amazing explanation. I have a basic question that while designing boost converter for 5kW , the peak current comes to be 26A which makes area product very high. Do we have to take peak current in Inductor or some other current?

[@mankapowerelectronics364]

Thank you for your kind words. We always consider peak current in inducture design. If you find difficulty designing one big inductor then you may design few inductors with lesser ratings and connect them in parallel to get total desired rating. All the best!!

[@arrshithrg5359]

this is better than nptel inductor design tutorials

[@mankapowerelectronics364]

Thank you for your kind words!

[@piyalharshadewa1280]

First,Your video is very usefull and thank you ! ............... And let me know how i can download specified ferrite core data sheet??(0_43825TC)

[@mankapowerelectronics364]

Thank you for the positive review. You may google the part number and find the datasheet online.

[@RAJANVAMJA]

It was a really good experience to learn it. thanks for sharing it.

[@v1slayer297]

Love and respect from pakistan, sir!

[@م.عبداللهالعصري]

Wonderful work .. Can you help me design ferrite transformer The input voltage is 100v ac to 240v ac The output is 4.5v 2A .. but the output includes three coils each one gaves 4.5v 2A You can use EE-core The frequency is 25 kH Thank you ..

[@amadobr]

Excelent document! Now, taking into account your example, as follows: calculus of an inductor with L = 500μH, Im= 5A, Fs= 25kHz, DC, I have a question. Considering that the coil is subject to an AC of 25 kHz plus a DC current, resulting in Im=5A , I ask: - shall be the wire diameter be calculated considering only the DC current effect , otherwise, the AC current (hence the δ skin depth effect) or a combination of both concepts? Thank you. Angelo.

[@niteshkumar6072]

Thank you sir. I request you to kindly make a video of designing of high frequency transformer containing both two winding transformer as well as multiple winding transformer.

[@ramagirikuna1586]

Hi sir great presentation..Thank you so much. Shall we follow same design approach for flyback transformer turns caculation...

[@riteshmaurya6908]

Hi....sah Its very informative. Can you please elaborate how does 10 ^6 comes in expresion of finding Area of product Ap for core selection.

[@mankapowerelectronics364]

Hi Ritesh, The unit of each quantity is converted into SI while substituting in equation. That is why you see exponent of 10 many places while making calculation. Hopefully this answers your questions.

[@riteshmaurya6908]

@@mankapowerelectronics364 thanks ...😊

[@pratapkuruva9072]

Good explanation sir, please make a video of high frequency toroid transformer design

[@jacobs7281]

By far the best inductor design video. Thank you so much for taking time to go through the theory and example At 28:01, The aw term in equation is an error? At 53:40, Isn’t WaAc given in datasheet same as Ap product? If so Do we have to do the Ac*Aw calculation since already given? 1:05:55, If outer leg is not half size of center leg , What is your best tip?

[@sandeeps7979]

Hello sir I have designed a step down transformer using ferrite core for my design I found turns ratio , but I need to know how much ferrite cores should I stack for getting power output of 5kw , can you please guide me sir , it’s for LLC converter .

[@pankajbadgujar4664]

Awesome video uploaded by you sir with all important details for designing. Thank you very much for this sharing. Can i have this notes in pdf from you if possible please share to my mail Sir i have gone through video I'm having problem with power inductor designing with air gap i have value for Ac, Aw, Imax, Bmax, D, Kcu, AL, Lairgap value in which i have 4 diffrent values for AL and Lairgap for which I'm calculating N. for different lairgap and AL they have calculated AL1 to AL4 again in nH but as per formula my answer coming in microH. And calculated N1 to N4 with this AL1 to AL4. For the same which formula they have used i didn't get it. I have try all combination but I'm not closer to ans. I will mail u same thing in the morning as it's to late now.

[@prabhanjanakumartripathy4140]

Did you make a video of how we make a motor with calculation

[@mankapowerelectronics364]

Hey, I don't have any video for motor design.

[@debasismohapatra627]

Hello sir,i want to design one Dc inductor with E-I type core .core material is sillicon steel.how to find the Al value of sillicon steel .i have two winding primary and secondary.so for area product formula which inductance value i need to use ,primary inductance or secondary inductance

[@vishalballal7609]

what is the calculation for 2 % inductance ,440volt,16amp,50hz line choke...

[@BeMuslimOnly]

It was a brilliant lecture. So many confusions got answered. Thank you ❤

[@UmeshYadavSDO]

i learn much more than our PE teacher... thanxs you sir..

[@mankapowerelectronics364]

Thank you Umesh for your kind words!

[@teslalab3400]

Thankyou so much for this video sir Expecting more videos like this

[@yunusemreozdemir1342]

Thank you for this video, it's really educative. I have a question. Aw equation seems false in 27:36. From your equations above, the equation result like Aw = Aw * aw. If you correct this equation, could you text a general message about it?

[@yogiranjit]

Hi, can you tell me for ferrite toroidal core till what value we can select Bm ?? and also till what power level we can use toroidal ferrite core?? or if you can give any idea that for which power range which core should be used??

[@sureshs5808]

Please mention what is maximum flux density we can go DC choke design using CRGO core.

[@satd2024]

Very useful thanks

[@dannyperry8070]

2 questions. I have looked at a few abstracts. On some they use the reflected voltage to calculate n and on others they use the vin over out. Which is correct? Also if Bmax is specified by the core and it is not exceeded in the calculations then why do we need the air gap. I understand that the gap changes the slope of the BH curve but is it required in all cases. Thank you

[@yogiranjit]

Hi, can you tell me for ferrite toroidal core till what value we can select Bm ?? and also till what power level we can use toroidal ferrite core?? or if you can give any idea that for which power range which core should be used??

[@sukhdeosingh617]

U are great sir. Very helpful video Sir. Kindly upload video on smps power supply designing. Thank you very much.

[@shyamverma263]

Hello sir, I have a request can u make a lecture or take a class on how to use kinect for hand recognition. (Opencv)

[@SanjaySharma-pw6ww]

Thanks for the video and valuable information you gave me.its a request pls improve the quality of visuals.

[@rakeshverma-cu8ug]

Actually I can't getting exact no of turn for actual rating ,I want to design each rating harmonic choke only one core 77337A7 by stacking core.

[@kebabsharif9627]

HI, I don't get, why you choose (@54 min ) 2 one and the 1st one although it has Ap near to your calculated value?

[@subhashdhyani743]

equation 7 in this video is somehow wrong please correct it. you will find it at 27.53 video timings.aw will not come there.

[@adityarawgautam3333]

Thanks for this video and nice explanation.

[@mankapowerelectronics364]

Thanks Aditya😊😊

[@titeman9374]

Sorry I guess you you convert mm^2 to cm^2 you are write

[@mankapowerelectronics364]

No problem. Good to see someone verifying the results!😊

[@rakeshverma-cu8ug]

Sir please call me immediately, I am facing to find no of turn for harmonic choke design

[@usmanhaider4653]

Great.👍 Question is that why books Arthur does not share practical information.

[@mankapowerelectronics364]

Thanks for appreciations!!! Actually you will find books where they talk in details about every aspect of design parameters. But those books will only be focused on one or few topics in detail.

[@hasanfarooq5923]

A very detailed explanation i get ..........not a single video is there on youtube which demonstrates in such detail as your video is... Thank you very much for your efforts.....do you have more videos for inductors....

[@mankapowerelectronics364]

Thanks for ur appreciation. Apparently I don't have anymore videos for inductor.

[@hasanfarooq5923]

@@mankapowerelectronics364 No problem, can i have your contact details.

[@mankapowerelectronics364]

@@hasanfarooq5923 Sure. My email: [e-mail], (M):[phone]

[@hasanfarooq5923]

@@mankapowerelectronics364 Thank you very much friend......

[@PradeepKumar-in2ej]

How to design line filter please explain

[@arvimgrana5856]

Correction in your first formula you can use both formula in one design especially in ferrite transformer design.Not "OR". Those two formula is inter related.. I've design ferrite transformer using both formula and it practically works...

[@mankapowerelectronics364]

Hey, here I have explained the use of these two formulae for designing inductors where core equivalent reluctance is of very important. In actual sense, both formulae are same if core reluctance comes same using these formulae. Otherwise, these formulae can result in wrong design too if proper care not taken. These two formulae can't give same design in all cases for your reference. That is why I have given two design examples to support the concept. In transformer we transfer energy instead of storing it (as in case of inductor). For transformer, design steps are different from imductor, where providing air gap might not be very important for high power application also. FYI in some transformer air gap is introduced for avaoiding saturation of core. I don't understand you commenting on validity of inductor design equations based on your transformer design experience.

[@lovelifeandunity1533]

Truly speaking sir this was an extraordinary demonstration about the details of inductor design. Thank u sir for sharing such a knowledge with such a dedicating effort.. I wish u make more electrical design videos like this.. Very helpful was this.. :::

[@mankapowerelectronics364]

Thank you for appreciation!!!!

[@deivid7257]

Exelente video

[@sayandv1991]

Thank you very much. I have suffered a lot from inductor saturation even after many attempts but this analysis has justified the saturation reason. Thanks a lot man. I hope if people donate their learning in this way, we can improve a lot. Thanks a lot.

[@mankapowerelectronics364]

Thanks Sayandev for your appreciation🙂

[@debasismohapatra627]

I want to design dc inductor which can store 60mj of energy without saturation

[@mankapowerelectronics364]

Hey, you will require value of both L and Im for designing inductor. Since, you already have energy need to be handled by inductor, u only require either L or Im and compute other (Im or L) from equation E=0.5*L*im^2

[@subhashdhyani743]

we want the same for transformer design for SMPS. When we expect the same

[@titeman9374]

Please my problem most time is how to figure out the value of an inductor i need to design or wind .Fore instance i need inductor smoothing (filtering) AC ripple after rectification ,please can you help me on this issue. Thanks

[@mankapowerelectronics364]

I am busy these days with my course work and exams. Unfortunately, I can't help you this moment. You may follow some design steps available for your application. Sometime finding correct resources is also difficult but you should be able to get, it just takes time.

[@omarromerosahagun679]

Thanks for the video! The information is very helpful. I would like to ask for a clarification regarding the selection process for Bmax in the equation Ap = L*I^2/(Bm*Kw*Kc*J) you show in the design example. For the design example, first using Ferrite core, you chose Bm = 0.2 T based on the graph from Core Loss Vs. Flux Density (Gauss) (time 29:30 in video). This value makes sense when using ferrite core, because for B = 0.2T at 25 kHz you would have a core loss of 70 mW/cm3. In the video you mentioned using 100 mW/cm3 (time 30:45 in video) is a good safe value and that we should really look into the thermal management in the PCB. Now when you change to the iron powder core, you mentioned that due to the different chemistry you can go higher than 0.2T, which makes sense when using Iron Powder (as you introduce a distributed air gap), so you chose a value of Bm = 0.35 T for 25kHz (~1:09:00 in video), then mention that we could go for a higher value than this (0.5-0.8 T), and then select the core T150-60 from MicroMetals. Here is where the question comes, according to the datasheet from Micrometals for the core T150-60 (see link: micrometalsarnoldpowdercores.com/pdf/T150-60-DataSheet.pdf), when you see the graph from Core Loss Vs. Flux Density (Gauss), you can notice: 1) At 25 kHz and a Bm = 0.35 T (3500 Gauss), you would have a core loss of 10,000 mW/cm3, which is 100 times more than what you originally had with the ferrite core in the first part of the design example. 2) Also choosing a Bm of 0.5-0.8 T at 25kHz could get complicated as the reference line pretty much disappears after 0.35 T (not sure if you could consider it linear at all time). Could you please elaborate on these points? i.e. is T150-60 still a good selection even with the mentioned high losses? Is this something you considered during the calculations or were you neglecting these thermal losses? Would you rather go with a different iron powder material mix to lower thermal losses? If you choose a Bm = 0.5 at 25kHz, would you extrapolate the core loss? How would you have chosen Bm if you had only considered the iron powder core for the design example? (would you have gone directly to the graph from the T150-60 and chosen 0.35 or a different value?) Thanks!

[@mankapowerelectronics364]

Hi Omar, thank you very much for your questions. While making this video, I hadn't opened the iron powder core (T150-60) and looked the core loss graph. But I did now and found what your are saying is absolutely right. The core loss will be higher in the iron powder core. I had chosen the Bm value for iron powder core from my experience during my Bachelor's final year project while interacting with inductor manufacturers. The main advantages of using iron powder core is that air gap is distributed throughout the core (Hence the loss is uniformly distributed throughout the core) and the saturation flux density is higher (even more than 1T for most of the material technologies) [1,2]. Further the core losses in inductors in DC operation is way lesser compare to the AC operation. The area under BH curve for one period is majorly decided by the inductor current ripple, in DC operation the ripple current is lower compare to the AC operation. Generally, the core loss graph is given for the AC operations (X-axis : Bpk - Peak AC Flux Density (gauss)). For DC operation one can make some exceptions and go higher Bm value without actually increasing the core loss significantly but again the loss depends on current ripple; if the inductor is designed for higher ripple current then surely core losses will be higher. But cooling iron powder core is easier compare to the ferrite core (where the core loss is mostly concentrated around the air gap [1]). But ultimately, the designer should make the final decision based on the space available in the device for the inductor, cooling facilities and cost. But in the AC application, the core loss in the iron powder core can't be ignored and one has to consider all aspects (thermal, cost, core size requirement and so on) before finalizing the core. Choosing higher Bm will surely reduce core size and hence form factor of the device and cost. In many applications, where space and higher temperature rise in the iron powder cores are insignificant compared to savings in costs, iron powder cores offers the best solution. Once again thank you for your questions and feedbacks:) 1.electronics.stackexchange.com/questions/83876/advantages-of-using-a-powdered-iron-core-for-an-inductor 2. www.coilws.com/index.php?main_page=page&id=41

[@szekerespista3758]

Wow! 👌Thank you! Subscribed in your channel! You are a very good teacher. Your teaching method is clear, easy to understand. You are a blessing for your students, and for all of us by your KZbin videos! God bless you and your family!

[@mankapowerelectronics364]

Thank you Szekeres for your kind words😊

[@edwardtsang3243]

Excellent video on designing HF transformer

[@AVANGuAR]

Great video! The best one I've seen. Can you share the google document?

[@mankapowerelectronics364]

Thank you for your kind words. Here is the link for the google document drive.google.com/file/d/1SkMaJoXevTSEU77tZwbjIIqb9oMlrl_i/view?usp=drivesdk.

[@happysharma9582]

Sir how to design led bulb inductor

[@kuldeepjayaswal9933]

is L umand book explain it clearly ? i need 280uh inductor for which i get 55 turns with 20swg wire. what is chance

[@mankapowerelectronics364]

Hey, L umanand book is good book to start with but try to follow my steps because it is more generalized of steps given in L Umanand book. Regarding your design, for the inputs you have provided, I can't tell if ur design is correct.

[@kuldeepjayaswal9933]

ManKa Power Electronics i have designed exactly as per L.umananda ....but i dont think that with 55 turns with 20SWG wire size i get 280uH inductor valie. can you pls comment

[@harshvardhan8592]

sir very helpful lecture

[@kamleshpanchal8661]

Thank you so much 👍

[@yogiranjit]

And also like how are u deciding the Bm value based on frequency?

[@RainLovesCobain]

you determine how much core loss is allowed and you also know the operating frequency

[@trananhtuan6317]

thank you

[@sunuk1915]

Toroid inductor where's air gap? Still it's very high efficiency

[@ramagirikuna1586]

Hi .., Sir Already addressed in the video session that toroid not have air gap we have to create by cut into desired lenght as per the design approach use of high precision laser cutting method....

[@rohitjesusahayam9656]

Thank you for this amazing video. Cheers!!!

[@mankapowerelectronics364]

Thanks Rohit!!!

[@subhashdhyani743]

great!.....nice explanations

[@Pudersepp]

Thank you!

[@vishalballal7609]

superb video...

[@AS-zs7jw]

Thank you sir for your video, i have question about iron powder cores, that in EE, EI core we can set the air gap accoring to our current to avoid saturation, but as it is said that in iron powder toridal cores air gap is distributed, can you please provide any data where we can find the effect air gap of iron powder core (which will be fixed value for a given toridal core size), so we can find the saturation current of given size toridal core, please answer my question thank you

[@mankapowerelectronics364]

Thanks for your question. It might not be a good idea to add an additional air gap in the toroidal core which already has distributed air gap (you may choose the next available toroidal core which meets your requirements). Incase you would like to add additional air gap in toroidal core which already has distributed air gaps then you will require to consider reluctance of both the core and the air gap to find the equivalent reluctance of the inductor. Note: The effective reluctance of the core can be obtained using given AL value of the core. You may try these maths simply by yourself by following the concepts discussed in the video. Maybe we can discuss further after you have obtained some equations and still have some doubts. Thank you.

[@AS-zs7jw]

Sir thank you for your reply, as for ferrite core inductor we use 0.2T as saturation Bmax, for toridal iron powder core what is Bmax? aslo i do not want to introduce air gap in toridal core, but want to know the quantity of already available distributed air gap? for 100 amp peak current and 18uH what size of toridal iron powder core i should use? sir i'm using your method for core where we can introduce air gap after calcuting according to our current rating and it is fine, but now i want to use toridal iron powder core , which have distributed air gap, but for iron powder cores , i donot know the Bmax, value of distributed air gap in mm, so not sure for any current rating i should use which size of iron powder core? can you please please make a video on iron powder cores with an example in future , where you will not add air gap but will select core with distributed air gap for your current rating , you have already done an excellent job by making this video, thank you

[@mankapowerelectronics364]

@@AS-zs7jw You may follow the second example explained at the end of this video where the a dc inductor is being designed using toroidal iron powder core. Also go through the comments of Omar ramero sahagún (you can find it while scrolling down the comments of this video): this might help you to get an idea of what value of Bmax you can choose while designing inductor with iron power cores.

[@AS-zs7jw]

Thank you sir!, we are looking for more such concise practical experienced based knowledge videos from your side. waiting for for your more videos.

[@Rajeev1082]

Good keep it up

[@pcm7045]

Good effort bhaut achha 😁

[@mankapowerelectronics364]

Thank u babul