1000w smps based on LUDO3232

U

Upik

Member
How to correction of numbers 5 and 6, ??? is it placement of fuse after filter, ??? diode mur460 must be direct to mosfet drain or how, ?? i take in the path, though far. If i replace with igbt, does pin foot is same, ???
 
Silvio

Silvio

Well-known member
1) IGBT look ok and pin configuration is the same as mosfet
2) MUR460 direct to collector, emitter of IGBT look at my schematic 1000w smps
3) Placement of fuse correct but you can put away from heatsink and components closer together
4) Traces (5-6) make them more strait and parallel.
5)The inductor is not needed for the aux supply as now you have normal transformer not small smps like I had.

UPIK IGBT.JPG
 
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U

Upik

Member
Thanks a lot mr.silvio, i will fix the pcb. In my country the max ac voltage is 220vac. Sometimes only 180vac. I will add feedback on the output.
 
Silvio

Silvio

Well-known member
In the transformer details that I gave you have the volts per turn, now you can adjust turns according to your need. Do not forget that for regulated output you need at least 25 to 30uH inductor on each side of the output. You also need around 25 to 30% more peak voltage to compensate for voltage drop in inductor to get good regulation at high current.

Change also the output diodes, 15A each is not enough you need 20A now as the peak current is higher, You may also need to double IGBT use 4. 2 in parallel on each side of the HB

You also need higher voltage rating capacitors on the output, Be careful and see that peak voltage on secondary does not exceed capacitor voltage because they will not last very long.

You also will need place on pcb for minimum load resistors 5 to 10watts

Good luck Silvio
 
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U

Upik

Member
Can you give igbt schematics in parallel, ??? can IC provide supply to 2 IGBT each, ?? need to add GDT, ??
 
Silvio

Silvio

Well-known member
No I do not think you need to add GDT to drive IGBT in parallel as long as the smps works in full duty cycle. The reason is that if the smps has to work with low pulse width then the bootstrap capacitor will not have time to charge properly and problems may arise.
If you are going to use feedback then you have to use GDT for sure switching on the IGBT. Here you have to be careful and see that the switching pulse must be at 12- 15v at all times.
Adding feedback may not be as simple as it seems and if you have no oscilloscope you cannot see what is happening.
I never built an smps with gate drive transformer and I have no detail for it.

I will add photo of parallel IGBT from home as I have a problem with uploading files from here.

Regards Silvio
 
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U

Upik

Member
Silvio said:
No I do not think you need to add GDT to drive IGBT in parallel as long as the smps works in full duty cycle. The reason is that if the smps has to work with low pulse width then the bootstrap capacitor will not have time to charge properly and problems may arise.
If you are going to use feedback then you have to use GDT for sure switching on the IGBT. Here you have to be careful and see that the switching pulse must be at 12- 15v at all times.
Adding feedback may not be as simple as it seems and if you have no oscilloscope you cannot see what is happening.
I never built an smps with gate drive transformer and I have no detail for it.

I will add photo of parallel IGBT from home as I have a problem with uploading files from here.

Regards Silvio
Click to expand...

Well mr.silvio ,, i will leave about feedback. Now i am fixing pcb.
 
U

Upik

Member
Hi mr.silvio, i only have some rur3060 diodes and some 30cph03, is that a problem, ??? diode with 2 legs only mur1560 i have
 
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Silvio

Silvio

Well-known member
Upik said:
Hi mr.silvio, i only have some rur3060 diodes and some 30cph03, is that a problem, ??? diode with 2 legs only mur1560 i have
Click to expand...


Both diodes are good use what you think fits best. They are a bit over rated though.
 
U

Upik

Member
Hi mr.silvio ,, if i change the frequency on the pwm card to 25khz, will the DT Resistor be the same, or have to adjust it again, (without feedback)
 
Silvio

Silvio

Well-known member
Upik said:
Hi mr.silvio ,, if i change the frequency on the pwm card to 25khz, will the DT Resistor be the same, or have to adjust it again, (without feedback)
Click to expand...

I know that the dead time will change with frequency but I am not sure which way it will go (smaller or bigger) when you change from a higher frequency to a lower frequency. I understand that you are saying that you leave the same value of resistor that you used at 65Khz.

I am sorry I do not remember this maybe another member can help you here.

Regards Silvio
 
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