Miller DX200 welder SEMIKRON SkiiP 33NEC125T2 Power IGBT Module

I do not take credit for someone else's work.

Here is the assumed topology of the OEM diagram:

I am doing in this order:

Separate Diode Power Bridge Rectifiers from IGBT components to reduce a heat spread.

OEM PART IMAGES:

Now side by side:

Here is someone else's work so I do NOT take credit for reverse engineering ( also this all just assumption based on this diagram )

Based on the diagram on the image following components is no longer available for sale:

Component released on : July 2007

And last but not leased another member of this forum made a PCB preview ( PCB not complete and needs redesign )

it seems the bottom right corner of the original has 4 IGBTs in parallel which are used for PFC, not really critical if higher amps IGBTs used.

Another thing is I will attempt to measure the threshold value of Vge for main IGBTs. Will publish when I'm done, so we can compare with FGL40N120 on schema above.

The first datasheet shows Vge (th) threshold in the range of 5 to 6.5v w/ average 5.8v and that measurement is done at 6ma in load, typical value of Ic is 250uA, not sure why german company decided to go w/ 6mA, probably it is their standard, but it's Ok.
As of second datasheet above does not publish Vge threshold at all, so, you can only guess.

Also, there are 4 generations of those SkiiP Power Modules and all are different as designed at different time,

So, guessing may get us in trouble. Another parameter is Vce sat - also important as size of the radiator directly depends on the value of voltage  drop on collector-emitter at max load let say 50A will get us to let say Vce sat = 3v will be needed to dissipate 150W where 3v drop is a real number from datasheet above, and that is way over for DX200 radiator. So, less value is a preference, 

As I've heard this 33NEC125T2 is heavily customized specifically for welders schematically w/ the best IGBTs used at that time, so I'd be careful, but sure you can experiment with what you have, you gotta start with something. Meantime, I'm thinking about the way to take measurement without destroying good power module which I can't afford, and we need to get a close match by most critical parameters and better match those IGBTs will help us to get a stable outcome.

mb443 said:

As I've heard this 33NEC125T2 is heavily customized for specifically for welders

I am sure will find solution :)

Seems like I wasn't able to take measurements due to my power module is not responding to anything due to possible damage from gates side while Collector-Emitter side doesn't have any visible burns and crystal looks ok.
As requested I will add the schema I used to measure Vge threshold.

To measure voltage on the gate connect one multimeter set to DC voltage and begin raising it from 0v and up watch for current in Collector when it reaches 6mA and that would be a Vce threshold level. Then Vce saturated can be also measured with multimeter set on DC voltage connected to Collector-Emitter and watch when voltage stop dropping, so the lowest voltage would be your Vce saturated. 

Warning! Since you will fully open IGBT, the maximum current will be going through transistor, so radiator is a MUST use as for example with 60v power supply and 20ohm load there will be 3A current going through IGBT and with roughly 3v saturation there will be 9Watt power dissipated as a heat. So to prevent IGBT from going into cardiac arrest, use radiator or make your measurements very quick. Radiator is also suggested if you interested in stable values of measurements. Or simply DO NOT measure Vce saturated, only Vge th is the most interested parameter anyway.

in case anyone cares, the fragment on the bottom right is simply what is inside of any IGBT, as many think it's a new technology but in reality it's just a mosfet + bipolar transistor put together along with snabber diod into one case and call it IGBT, similar to darlington transistor.

Your test design is correct, however, instead of R* 5 ohm load replace with lightbulb.

Also, if you are using  dual power supply make sure to combine GND.

And yes while conducting test PM must have heat dissipation / radiator.

Schema seems ok, as of PCB I can't really see the whole board as image is cut on a sides. And I'm pretty backed up with other things nowadays, so whenever i have time. Also, did you succeed measuring your PM? Wondering what is Vge threshold on those?

I am no longer interested working on this project.

Seems to me besides two people nobody else step forward.

I have specially missed one pin on Schematic design, after I ask you to double check my work, your reply seems OK.

Therefore, in conclusion --->  working on this project is a waste of time.

I am moving My work to my own private website.

What is Your site? 

I stopped working on this project.

Website: www.369support.com/1/

However,  Site is closed to public... personal/internal  use only.

If you need help let me know.

Thank you.

Hello, I am interested with your project,  how i can register at your website?

Hello, I am interested with your project,  how i can register at your website?

Sorry my site for my personal use only.

If you would like we can continue to work on this project here in this forum / board.

However, I would like to see other members step into this project and share their finds and test results.

If someone is interested I can repost Power Module images of reverse engineered info with "mb443" and i.