crazifunguy
New member
**required core too large**
DIY SMPS 1.4 Kw WITH CCM PFC
- Thread starter crazifunguy
- Start date
I think, you should enter RMS current in formula, not PEAK. other wise it will be very big.
or use two small T200 cores, as another option.
See my 1.2KW coil
crazifunguy
New member
It seems that no matter what I try 30A requires a massive inductor even with 500Khz. I am gonna explore new ideas that use multiple inductors. I am still thinking that this type of power supply at this power level is just not ideal size or cost wise.
Show me snap shot of your screen, with values, lets see whats going on your side.
A 1200W SMPS with PFC, is not an easy goal!
Dont Give Up..
Thanks
crazifunguy
New member
Here are the Inputs - Outputs - Results Using the TI Calculator UCC28019
I am afraid that 300uh is incorrect value, since that IS the actual value you will use *after you make your coil* and mesure it. but the calculated one is 196uh, that gives a SMALLER core size. and you need to enter that value!
Check and confirm
crazifunguy
New member
Well I decided to check into the UCC28070 Controller that uses an interleaved design. There is a sample design of a 1200W PFC and it uses a tiny inductor. The specs of the design arent mentioned of coarse. The inductor is 78uH. I wish I knew the current for the inductor. The design calculator only gives the RMS current.
http://focus.ti.com/docs/prod/folders/print/ucc28070.html#toolssoftware
http://focus.ti.com/docs/prod/folders/print/ucc28070.html#toolssoftware
Is there a way to change the switching frequency of UCC28019? I know that the spreadsheet is set to calculate at 65kHz. Microsim is correct as 196 vs 300uH is significant. If the switching frequency of UCC28019 can be changed to 100kHz, the required inductance value at 30% ripple will be lower, therefore yielding a smaller inductor. The peak current of the inductor is not going to change much by increasing frequency but the decrease in required inductance is what will give you a smaller inductor.
crazifunguy
New member
The frequency is fixed with that controller IC 
Is it safe to use just the RMS current for the inductor design?
Is it safe to use just the RMS current for the inductor design?
The frequency is fixed with that controller IC
Is it safe to use just the RMS current for the inductor design?
Calculate on 17 Amps, Even 15 AMPS, using that PFC for SMPS *Audio* applications wont be a problem
I dont think there will be a problem *in prototypes*. use 17 AMPS. RMS Current is OK, I used RMS, Will show results when other parts arrives.
If you have access to those cores, get T200, T250, T300. And you will see how things will go, I dont Expect *for my self* to succeed in PFC from the first time.
Just give it a try..
Sierra
Valve Lover!
Mains Fuse
Let me clear one thing for all.
Mains fuse for such Power supply with PFC should be 10Amps, I never saw any smps with PFC uses 23Amps mains fuse.
If we are going to use PEAK current as refrence, then a party with 4000W power amplifiers will need more than 80AMP running at 110VAC.
I dont think this is true.
Let me clear one thing for all.
Mains fuse for such Power supply with PFC should be 10Amps, I never saw any smps with PFC uses 23Amps mains fuse.
If we are going to use PEAK current as refrence, then a party with 4000W power amplifiers will need more than 80AMP running at 110VAC.
I dont think this is true.
crazifunguy
New member
I agree with that. I am going to just prototype a design using the worst case current rounded. 85V 1400W.....Approx 15A. Once I have something to play with I can test it and see if it can handle the current draw.....If it fails I can always rebuild it. 15A sounds like a good starting point. CHEER.... Happy New Year...
Pfc
While you are at diysmps, you will not fail!
Do what I told you, I am telling you true results, Unless you will use this PFC for constant supply, other things will apply.
While you are at diysmps, you will not fail!
Do what I told you, I am telling you true results, Unless you will use this PFC for constant supply, other things will apply.
CobraNet
Member
You got any results?
Have you calculated values for that chip using calculator?
I would appreciate if you show me your progress
Thank you
crazifunguy
New member
I am back....I have been burdoned with too many things keeping me busy. I am going to continue to work on this design until completion...more to come!!