winding ferrite core transformer for smps

[--BawA--]

i am making a DC DC converter , after doing some calculations i found that ,i have to wind the etd49 transformer with 1 primary turn and 34 secondary turn , current which can flow through the primary turn is around 50 ampere , and frequency is 50KHz , so i decided to use few strands of 23awg wire to make a litz wire., the problem is if i wind the primary turn , the 90% space of the bobbin is still empty ,which i think is not good(correct me if i am wrong)
i want to know ,how to wind this transformer effectively if primary turn is too low, ?

 

[FvM]

You need more than a "few strands" AWG23 for a reasonable 50 A winding. In terms of skin depth, AWG 23 strands are already less than optimal. Good stranding is required anyway to share the current uniformly between all wires.

Referring to ETD49 power capacity numbers, 30 to 50 % winding area utilization would be expected at least for 500 or 600 VA push-pull transformer.

 

[unknown230]

with single primary winding, what value of Lm you got? Generally this Lm need to be more.

 

[--BawA--]

You need more than a "few strands" AWG23 for a reasonable 50 A winding.

I have used 17 wires in parallel to make make a litz wire.

with single primary winding, what value of Lm you got? Generally this Lm need to be more.

what is Lm ? btw i have got Bmax as 1800 G.

 

[unknown230]

Iam talking about the magnetising inducatnce

 

[FvM]

btw i have got Bmax as 1800 G

Are you still using CGS units in engineering? My old physics book (1971 edition) still has it, but 70th ferrite databooks are calculating flux in T.

 

[--BawA--]

Are you still using CGS units in engineering? My old physics book (1971 edition) still has it, but 70th ferrite databooks are calculating flux in T.

sir, i was reffering the power supply book of marty brown,

1)one more thing to ask , if i connect a (music system) to the inverter , there is a humming noise coming out of music system ,however on grid supply ,no humming noise comes , my inverter is sine wave , but when i connect the load ,it distorts, ,,,also a noise always comes from the filter inductor of the h bridge ... what could be the possible problem for that?

2)if i increase the no. of sine table entities, will it improve the output waveform?

 

[--BawA--]

FvM, How to calculate magnetising inductance of a transformer?

 

[D.A.(Tony)Stewart]

I have used 17 wires in parallel to make make a litz wire.

what is Lm ? btw i have got Bmax as 1800 G.

I suggest you use this although it does not have torroids, it has all the calculations for ferrite materials and different designs.

https://www.ferroxcube.com/FerroxcubeCorporateReception/datasheet/sfdtsetup.zip

Here are some ferrite specs in the units of G you are familiar with. 10k Gauss=1Tesla
https://www.cfe.com.tw/4-sendust/iron.pdf

 

[Velkarn]

i want to know ,how to wind this transformer effectively if primary turn is too low, ?

i think, better way is to use copper foil for this one turn

 

[--BawA--]

Kindly have a look on post #8.

 

[FvM]

How to calculate magnetising inductance of a transformer?

L = Al* n²