My 4Kw smps finished

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#22
Andy F said:
Well explained. The supply is on hard swiching mode during idle times(you can confirm this as the Igbts get warm and looking at scope on the secondary winding of the current sense coil) but the current is very low so the devices dont suffer, as soon as the load increases the supply approach resonance and current becomes more sinuoidal shaped so some self regulation is obtained as you are approaching resonance point as the current grows,the duty cycle is always near 50% you cant get uncontrolled voltage increase on output due to pulse modulation and when the current is moderate the Igbts are a bit colder than at idle due to the sinuoidal current that is forcing soft switching through them.
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this topology reminds me of induction heating appliences. the topology is almost the same and these power levels are justified.

Thanks a lot Andy. You opened up a new area of SMPS desings here on DIYAUDIO.
 
#23
Hello Andy...

Also as i can see from the pictures attached you don't need to use inductors from diodes to caps in the secondary side. (this is because the courent is sinewave i guess).
so my question is:

does this topology use normal caps at the secondary side (NOT low ESR)?

best regards,
 
#24
Hello Andy ...

do you switch the IGBT's while 0 tranzitions (ZCT, or what is it called)? because if so you will correct the losses while the smps is without load and the IGBT's won't go warm as you said.

Best regards,
 
#25
Hi:

I am not using very low ESR caps, but good quality ones from Su'scon or Teapo brands (105º rated) for sustained LF applications I did a capacitor bank outside the smps as an option,I forgot to mention that the supply has also the 2 outputs independent and floating from ground for grounded bridge applications when needed.
 
#28
ok ... true ... but for exampletoday I powered a smps that i'm working on ... half bridge 1kw bla bla bla.

i taught that the scope went crazy when i measured the output (without the inductors)

EMI is a big problem in smps

hope it is worth the risk

best regards

EDIT:

I'm just not concentrated. Of course you don't need inductors the current wave form is sine 🙂

My bad
 
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#30
As i understood till now:
-regulated smps use inductors at secondary,need feedback, have high ripple swithching (hard switching), need low esr caps
-unregulated resonant ones have fixed freq and dutycicle, no need for inductors at secondary, no need for low esr caps, have better power capability in half stage and slightly lower eficiency if not combined with a pfc

best regards,
 
#31
Hello Andy ...

Andy F said:
Hi:
The transformer is an EE65 3F3 core wound using Litz wire and interleaved windings to keep leakage inductance as low as possible (actually 1uH or so)
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by interleaved you mean 1/2 primary then 1st secondary, then 2nd secondary, then 1/2 primary?

because i have made a trafo (with ETD44) yesterday with homemade litzwire (60 strands of 0.08 CuEm in primary and 30 strands of 0.08 CuEm in secondary) and I was amazed with it's small losses. don't have L meter to measure leackage inductance but i think it is low.

regards,
 
#34
Hi Savu:

I dont know, it depends on remaining calculations, you must do a whole calculation set for the transformer based on Power, dead time, voltage, current, core specs and a lot of things more before to get the wire diameter. For sure, you must get the calculations needed over the net very easily. If you dont do that the other way is to apply brute force and trial and error, very time consuming and not optimal at all.
 
#35
Hy Andy...
I am making the design after a schematic that works. the only problem is that nobody spoke of the conductor section. this is my problem. i want to draw 1kw peak out of it. it think the design was LUKA's. need to check that out.
i will do the calculations tonight and redo the winding tomorrow.

thanks a lot Andy
 
#40
81bas said:
EXACT copy with SLIGHT modifications 😀

Have you some photos of this glorious P***-A*** original design? 🙄 Simply post the photos of PCB here, we will compare then 😉
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81bas.

the modification he dose is nothing comparable for you. either for me.

I am not planing to engage with you in some fights.

I will post the original file later. dont belive that man. its not his design he purchased it. COMPLETELY .

Its a copy, or its the ORIGINAL POWER SUPPLY OF P*** A***

I can give you part numbers he uses, but I wont do that, he must make some cash from that supply I dont mind, but dont say its his design.

See you later 81bas. and be good with me. I have nothing againest you.
 
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