SMPS EMI Stage - diyAudio
Go Back   Home > Forums > Amplifiers > Power Supplies

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 22nd November 2009, 08:28 PM   #1
Account Disabled
 
Join Date: Oct 2008
Arrow SMPS EMI Stage

It it OK to split the

Filter Stage, Bridge, The 2200uf/200V capacitors/Delay ON circuit to a separate board?

AND to take the + 0 - 360V through a cable to the switching board that CONTAINS.

IGBT, ETD59, Output Diodes, Driver SG3525, Output Capacitors, Current Limit, Short Circuit protection.


I don't know if it OK to do that!

Please advice.
  Reply With Quote
Old 22nd November 2009, 08:43 PM   #2
Eva is offline Eva  Spain
diyAudio Member
 
Eva's Avatar
 
Join Date: Oct 2003
Location: Near the sea
Send a message via MSN to Eva
The input capacitors, switching stage with drivers, transformer, output rectifiers, output inductors (if any) and output capacitors should be together because high frequency high currents are flowing on these paths and parasitic inductance matters a lot.

The control circuit may be in another PCB as long as signals are interfaced properly.

Input EMI filter, input rectifiers and softstart may be in another PCB too, or even point to point (for early prototypes), as only low frequency currents flow there.

If you are not experienced, start to visualize things in terms of parasitic inductances and capacitances that form LC resonators. For example, the inductance of the 2200u 200V capacitors in series, together with the inductance of the leads of the IGBT package and PCB tracks, will resonate with the internal C-E capacitance of the IGBT that is turned off, typically between 10 and 50Mhz. Parasitic winding capacitance and the inductance of the connections to that capacitance may also add resonant modes.

These resonances work like the strings of a guitar, they are plucked on each switching event and will keep singing (and producing EMI) for a certain time if proper damping is not included. The higher the parasitic inductances and capacitances, the more energy will have to be dissipated in the damper snubbers.

Wires are highly inductive and very good EMI radiating antennas (in comparison to a PCB with ground plane) so they have to be avoided completely in high frequency paths.
__________________
I use to feel like the small child in The Emperor's New Clothes tale

Last edited by Eva; 22nd November 2009 at 08:54 PM.
  Reply With Quote
Old 22nd November 2009, 09:45 PM   #3
Account Disabled
 
Join Date: Oct 2008
Cool OK

Thank you EVA,

but your answer is complex for me to understand, since I am not that expert in SMPS.

Therefor you recommend to put all the stuff on one PCB? that will be large!

Regarding the ground plan, it should be connected to witch ground? OUTPUT or INPUT?

That circuit will operate at 125KHZ, what power do I expect from that frequency with ETD59

Can I get 1.7KW Continues?




SEE CAPACITOR, LINE FILTER



Thank you

Last edited by microsim444; 22nd November 2009 at 10:00 PM.
  Reply With Quote
Old 22nd November 2009, 10:09 PM   #4
Account Disabled
 
Join Date: Oct 2008
Default Picture

Please check that PART of schematic, and advice what I can split
Attached Images
File Type: jpg Photo-0261.jpg (236.3 KB, 278 views)
File Type: jpg Untitled.jpg (52.7 KB, 266 views)
  Reply With Quote
Old 24th November 2009, 11:10 AM   #5
Eva is offline Eva  Spain
diyAudio Member
 
Eva's Avatar
 
Join Date: Oct 2003
Location: Near the sea
Send a message via MSN to Eva
I think you are trying to go to fast. If you make a prototype without understanding how parasitic Ls and Cs work, many unexpected failures and dozens of blown IGBT/MOSFET are likely to be the result.
__________________
I use to feel like the small child in The Emperor's New Clothes tale
  Reply With Quote
Old 24th November 2009, 01:08 PM   #6
Account Disabled
 
Join Date: Oct 2008
Default Suggeset?

Quote:
Originally Posted by Eva View Post
I think you are trying to go to fast. If you make a prototype without understanding how parasitic Ls and Cs work, many unexpected failures and dozens of blown IGBT/MOSFET are likely to be the result.

Hi EVA.


What do you suggest?

I already have all values for all components.

and I am sticking to the schematic, and parts values.

The only thing I dont know is the output Transformer, witch I will use ETD59. with LITZ Wire


In my previous project, I had dozen of blown MOSFETS in that design. I dont know how to prevent that!



Please your advice.


Thank you EVA

Last edited by microsim444; 24th November 2009 at 01:14 PM.
  Reply With Quote
Old 24th November 2009, 01:38 PM   #7
opc is offline opc  Canada
diyAudio Member
 
opc's Avatar
 
Join Date: Oct 2004
Location: Ottawa, Ontario, Canada
Hi Microsim,

I'd say that splitting just before the rectifier would be wise, and in fact, it's good practice to keep the line filter isolated (shielded if possible) from the main supply to prevent injecting radiated noise back into the line after the filter.

The bulk capacitors after the rectifier need to be close to the IGBT's. Local decoupling is also a good idea. As Eva said, you need to carefully consider HF return paths.

As for the ETD49, you should have no problem getting 1700W a that frequency if it's designed correctly. If it's running at full power all the time, you'll probably need active cooling, and you'll have to balance out your core and copper losses in the transformer.

On another note, Eva is absolutely correct - you seem to be going a little too fast. Getting a supply like this to work and not pollute the entire house with EMI is not a trivial matter. Even with a full set of design skills, a fully functional supply, and an EMI lab, it's still a struggle to optimize for low EMI and meet standards. Without all of the above, you don't stand a chance. It's just the nature of high power switch-mode electronics.

I would suggest looking into a lower power project, and maybe using an integrated solution like the parts from Power Integrations. They make small integrated controllers/fets called Topswitch. You can use their software to design what you need (up to 300W I think) and at least that way you can get some experience with the other aspects of SMPS (transformer, line filter etc...) without taking on everything at once.

Best of luck!
Owen
  Reply With Quote
Old 24th November 2009, 07:52 PM   #8
Account Disabled
 
Join Date: Oct 2008
Hello.


I think that all of are right, BUT you are talking too professional also.

In my previous SMPS, (See Pictures) its not that professional, but that was my second project after building the K6 SMPS from (A&T LAB) That supply are crap any way, it failed.

The second one I built was better, I got +-80V 7.4 AMPERE. with good ventilation. I Tried it with power amplifier, things was very good ( I BLOWN UP MANY MOSFETS) i cannot deny that but DUE MY Mistakes.

In this new design I will try to eliminate those things with your help all !

See pictures
Attached Images
File Type: jpg Photo-0256.jpg (452.9 KB, 243 views)
File Type: jpg Photo-0254.jpg (478.0 KB, 207 views)
  Reply With Quote
Old 28th November 2009, 12:45 PM   #9
Account Disabled
 
Join Date: Oct 2008
Default Started

I decided to start the SMPS.


Attached is the PCB layout for the EMI filter BOARD. excluding the Bridge, Capacitors.

3d, PCB
Attached Files
File Type: zip EMI.zip (109.4 KB, 81 views)
  Reply With Quote
Old 28th November 2009, 04:55 PM   #10
opc is offline opc  Canada
diyAudio Member
 
opc's Avatar
 
Join Date: Oct 2004
Location: Ottawa, Ontario, Canada
Microsim:

I'm a little worried now... the Y-caps need to go to chassis, and I don't see any 6mm isolation on that PCB. This is basic safety, and needs to be followed. Those caps also need to be rated appropriately. The exclamation mark and triangle are on the schematic for a reason.

If you're not familiar with basic off-the-line switcher safety, I would strongly suggest you read up on it, and strongly suggest you not attempt any project that is beyond your abilities in the safety department.

If it ever caught fire and burned your house down, your insurance company would laugh in your face and you wouldn't get a dime. At least if you can prove due diligence you might stand a chance.

Also, you'll probably have problems with light-load stability with a very high power SMPS hooked up to a class AB amp with light bias.

Cheers,
Owen
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Aikido line stage - plus phono line stage cjkpkg Tubes / Valves 1 22nd November 2008 10:50 PM
Output stage biasing, with the driver stage andrew_whitham Tubes / Valves 0 19th May 2007 12:14 PM
Should I replace Scott 222C phono stage with Claret phono stage? Bing Yang Analogue Source 0 22nd August 2005 07:41 AM
Line stage preamp, based on SY's "Heretical Unity gain line stage" Danko Tubes / Valves 23 18th July 2005 05:07 AM
SMPS for Hi-Fi? mr_push_pull Power Supplies 4 12th November 2004 04:45 PM


New To Site? Need Help?

All times are GMT. The time now is 04:18 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2