300w smps need help with txfr calculation
- Thread starter sekhar
- Start date
Igbt
Have you tried to use IGBTs?
I would be interested into some oscilloscope waves while running the PFC at 90VAC.
If you dont mind
Have you tried to use IGBTs?
I would be interested into some oscilloscope waves while running the PFC at 90VAC.
If you dont mind
@microsims.............
i am in a bit of trouble........ i have calculated the details for the pfc inductor but it gives me 875microhenry and 238 turn .......... which seems absurd..... for a 400w pfc
here is my calculation....
vin(min)= 90V
vin(max)=265V
pout=400W
fsw = 100khz
Bmax = 0.25T
Ae = 0.97cm square
Core used ETD34 ferrocube...
ipk = 1.414 X pout/ 0.95 X vin(min) = 6.615A
ripple current =15% of ipk = 0.99A
Lcritical = 1.414 Xvin(min){(1-(1.414 X vin(min))/vout} / ripple current X fsw = 875 microhenry
no of turns = lcritical X ipk x 10000 / Bmax X Ae X 1000000 = 238
i have been refering to a pdf by metglass and some other online documents.....
kindly tell me what am i doing wrong .............
regards
sekhar
i am in a bit of trouble........ i have calculated the details for the pfc inductor but it gives me 875microhenry and 238 turn .......... which seems absurd..... for a 400w pfc
here is my calculation....
vin(min)= 90V
vin(max)=265V
pout=400W
fsw = 100khz
Bmax = 0.25T
Ae = 0.97cm square
Core used ETD34 ferrocube...
ipk = 1.414 X pout/ 0.95 X vin(min) = 6.615A
ripple current =15% of ipk = 0.99A
Lcritical = 1.414 Xvin(min){(1-(1.414 X vin(min))/vout} / ripple current X fsw = 875 microhenry
no of turns = lcritical X ipk x 10000 / Bmax X Ae X 1000000 = 238
i have been refering to a pdf by metglass and some other online documents.....
kindly tell me what am i doing wrong .............
regards
sekhar
I am not sure about that formula, since I never used it into my NEW PFC.
To simplify things.
In one commercial SMPS 400W, Input 100V AC, Inductor used is ETD29 with LItz Wire, 40 Turns, 260uH. I checked that myself! and it was true!
I am not sure if you need that number of turns. not more 40 ~ 50 I think.
Hope that helps..
I am not using ANY formulas. things are simple, very simple, dont make things complex yourself. you told me before that you had success with 500W. and now you are stuck?
There is a formula came with the UCC28019 CCM PFC Chip. it gave me 250uH of inductance, and I used same value, and I am happy.
BUT, core material selection was a complex task.
Thanks
@MICROSIMS.....
and yes i had success with 500W ..... but with a etd49 core of which i dont have the winding details.....this inductor was being used in some other product ...... So now i want to do it all on my own with help from u people........
is it possible that u share ur formula ................ and is it a problem if i ask for help in diyaudio................
regards
sekhar
and yes i had success with 500W ..... but with a etd49 core of which i dont have the winding details.....this inductor was being used in some other product ...... So now i want to do it all on my own with help from u people........
is it possible that u share ur formula ................ and is it a problem if i ask for help in diyaudio................
regards
sekhar
Last edited:
No no, I dont have problem to ask at diyaudio, I wish you luck.
I told you in the above replay, I DONT have, and I DONT use a formula.
Formula came with my UCC28019 Chip at texas web site.
If you are going to follow formulas in PFC, you will spend long time, most people at diyaduio will make your life worse, they will enter you into loops with informations drives you to the sea.
Make 1mh inductance, and give it a try, show me some scope waves. this is the shortest way for you.
If I would listen to others (specially at diyaudio) i would make nothing, because most of those people NEVER gives you what you want.
Check my 1700W PFC loaded here:- http://www.diysmps.com/forums/showthread.php?169-1KW-PFC-_-CCM-Power-Factor-Corrector.#post1306299505
as you can see in that thread, people ASKING for inductor design, its tricky, i paid 1000US$ for those Chokes, yes 1000US$. around 180US$ each
or you expect any DIY core in the market will do 1700W from 100VAC that easy?
and I can give you some guide lines.
thank you
@microsims
with 1mh inductance number of turns will be more than 250 hw will i accmodate so many turns in etd 34............................and i was checking other pfc ic i saw fan4810 and it uses a 500mh inductor with 59 turns......... wats is the formula for calculating number of turns......??????????? with my formula it gives more than 250 turns
regards
sekhar
with 1mh inductance number of turns will be more than 250 hw will i accmodate so many turns in etd 34............................and i was checking other pfc ic i saw fan4810 and it uses a 500mh inductor with 59 turns......... wats is the formula for calculating number of turns......??????????? with my formula it gives more than 250 turns
regards
sekhar
Pfc
In fan4810 Are they using same core as in your case?
I dont think so, either I dont know if they tell what core materials.
fill your ETD with turns, dont know how much it takes, give it a try man.
It will be the start, just do a proto type.
Toroidal cores are smaller in size + they have wide range of core material to select from. not like ETD series with limited core materials.
FAN4810 Inductor for 500W eval. Board http://www.fairchildsemi.com/collateral/fan4810_Choke.pdf
In fan4810 Are they using same core as in your case?
I dont think so, either I dont know if they tell what core materials.
fill your ETD with turns, dont know how much it takes, give it a try man.
It will be the start, just do a proto type.
Toroidal cores are smaller in size + they have wide range of core material to select from. not like ETD series with limited core materials.
FAN4810 Inductor for 500W eval. Board http://www.fairchildsemi.com/collateral/fan4810_Choke.pdf
@microsims
i have worked on prototypes before hand............... but that was in my company ........... now i am trying to do it for my self ............the prototype that i worked on used larger cores and running on lower frequency and had some other problem ........... this is a new pcb that will run on higher frequency and will be audio grade smps....
the pic that u see includes a pfc and a half brige smps........ i am stuck cause i dont know how to calculate the pfc inductor.................
regards
sekhar
i have worked on prototypes before hand............... but that was in my company ........... now i am trying to do it for my self ............the prototype that i worked on used larger cores and running on lower frequency and had some other problem ........... this is a new pcb that will run on higher frequency and will be audio grade smps....
the pic that u see includes a pfc and a half brige smps........ i am stuck cause i dont know how to calculate the pfc inductor.................
regards
sekhar
Sorry for coming in your thread, but I have one question about ETD39 core, I have few of these ETD39's Link To Datasheet ,but I cant figure out what material is it, and also other required specifications. Anyone have experience with these? Also inductance is 23,7uH, is that ok with half-bridge?
Link is not working.
ETD39 usually uses N27 N87 Core materials. Are you going to use it for Half bridge SMPS?