Inductor and transformer design methodology!

[goldsmith]

Dear All
Hi
Sorry for this delay , i promised to convert them to the PDF and then ZIP , and here it is : ( but you should excuse me for this delay .)

View attachment Ferrite.zip

Best Wishes
Goldsmith

 

[muhammadali_16]

u assume 100uH of inductor...!
how and why. i want to know how u assume that value of the inductor? is the value of inductor has no relation with the frequency or anything other?

and my second qus is about the J value in XL=jwL... as j is squreroot(-1). but here what should i do to calculate it

 

[goldsmith]

Dear Muhammad
Hi
About your 1st question : i assumed that i need 100uH inductor . you can change it with your desired value . for exmaple , perhaps , you , need a 500 uH at the out put of your SMPS ( it is example ) . i used that value , because i wanted to say , way of design with an example .
and about your 2nd question :
about , J , you shouldn't do any thing with that at my design , way , i just wrote it , because of the basics of circuit analyzing , and no thing else . ( it hasn't any effect at my way .)
Best Wishes
Goldsmith

 

[muhammadali_16]

can u tell me the way to calculate the inductor at the output?

i just want to make a supply using PUSH-PULL. no one here to tell anything about the calculation, btw ur notes are very helpful

 

[goldsmith]

Is your problem with designing the value of inductor at the out put of push pull , or with the number of turn and core ?

 

[muhammadali_16]

i just want to make a supply...... using ur notes, i have calculated the inductance and turns ratio of the transformer. the only thing which was missing the inductor calculations. i think i have missed inductor calculations.

 

[goldsmith]

I'm confused my friend ! what do you mean by : you calculations of inductor ? is your mean , that you have designed an SMPS , an now you want calculate it's out put inductor ? yes or no ? you told that you calculated the inductance but in the other words you said that you're looking for calculations of inductor ? clarify , what you need , please , thus i can help you , my friend .
Best Luck
Goldsmith

 

[muhammadali_16]

i want inductor calculation

 

[goldsmith]

again , you didn't clarify , it ! calculations of inductance ? if yes , what is the frequency of current through inductor and how much voltage do you need at out put of your SMPS ( as you said a push pull ) . and how much is your input voltage ( my mean isn't main input , my mean is the input voltage of inductor ( out put of secondary ) ?
Best Events
Goldsmith

 

[muhammadali_16]

ok.......

Input is 24V
Output is 3.3V - 3 A
Frequency is 100KHz
using Push-Pull terminology

 

[goldsmith]

well you can use these formula , simply : L=0.5*Vout*T/Ion
When i calculated it according to your specifications it given :55uH
Good luck
Goldsmith

 

[muhammadali_16]

can u also tell me snubber calculation??????

 

[goldsmith]

As i can remember i told you at your thread , how you can design it , forgot it ?

 

[muhammadali_16]

my mistake.... i forgot....

thx for ur kind consideration and help

 

[muhammadali_16]

using ur this note i m designing transformer. i met with a problem.

the transformer has following values
1 turn in inductance is 4uH

i wind 13 turns and got 100uH. as calculation said the value will be around 764uH.

i m confused

 

[goldsmith]

Dear Muhammad
Hi
Can you show me your calculations , step by step , thus i can find your error . ( i think you did a mistake in your calculations ) .
Best Wishes
Goldsmith

 

[muhammadali_16]

L1=764uH

1turn inductance of transformer=4uH (by LCR meter)

(N1/N2)Square=L1/L2

N1=1, N2=? L1=4uH, L2=764uH

N2= Square-root(764/4)

N2= Squareroot(191)

N2= 13.8

this means when i il wind 14 turns to transformer, i il get 764uH of inductance but im getting 100uH

 

[goldsmith]

well , your calculations seems ok , what is the type of your core ? is that toroidal ? or perhaps EE or EI , such as PQ series ?

 

[muhammadali_16]

its EI. i took it from PC power supply. (there are two transformer in PC power supply. this is the smaller one)

 

[goldsmith]

well , my prediction was correct . as you know for those cores , if you didn't match E and I correctly , together , the inductance will change . try to match them together , correctly , thus you'll see your desired inductance .