# $per watt IGBT brick VS throughhole?



## Nathan219 (May 18, 2010)

Has anyone done any testing on using multiple smaller IGBTs in place of the larger bricks? I am curious why the through hole IGBTs are one tenth the price and ¼ the power capability. Is the flyback diode the missing link that brings the prices in line? What are the considerations or circuits needed to ensure proper load sharing among the different modules? Mosfets could also be used, but I haven’t been able to find information on how the design criteria differs when multiple IC are used.
Thanks,


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## alexcrouse (Mar 16, 2009)

Nathan219 said:


> Has anyone done any testing on using multiple smaller IGBTs in place of the larger bricks? I am curious why the through hole IGBTs are one tenth the price and ¼ the power capability. Is the flyback diode the missing link that brings the prices in line? What are the considerations or circuits needed to ensure proper load sharing among the different modules? Mosfets could also be used, but I haven’t been able to find information on how the design criteria differs when multiple IC are used.
> Thanks,



I went with Bricks as they are easier to cool, and bolt to bus bars. It's pretty hard to move 1000amps through a PCB.


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## Nathan219 (May 18, 2010)

I was thinking about maybe 100-200 amps 600V for an AC drive. Less current less line losses is the hope anyway. Anyone know off a AC controller using smaller IBGTs or Mosfets or is building one themselves; let me know?
Thanks again,


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## steven4601 (Nov 11, 2010)

I chose bricks, using a PCB is possible, but a multilayer layer 70u..135u? PCB would be required. Also the PCB itself would need a fan. Wurth Elektronik used to make copper sheet inserts for PCB's. But they stopped and are now encouraging using the bricks. 


Here's what I have come up with. Its two flat copper bars, seperated by 0.3mm FR4. Its not perfect construction wise, but its effective in minimizing the inductance of the busbars.


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## Nathan219 (May 18, 2010)

How well does your design work?
If anyone has tried to make a inverter with the smaller devices what was your experience? I don’t know of another way to test the design models but to build some prototypes. If anyone has a stash of IGBT they want to sell let me know. I have been thinking, I know scary why couldn’t a controller be built that drives all types of motors? When driving series DC motors 1/3 the bridge for the + side of the motor 1/3 of the bridge for the – side of the motor. If you can make an AC signal the DC should be pretty easy, no offense Tesseract. The other IBGT could be implemented to drive the field in a sepex motor. Or better yet, duh tie one end of the motor on a DC system to the Battery pack, and use the IGBTs in parallel, to switch, which gets back to current sharing among power transistors.


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## steven4601 (Nov 11, 2010)

It is not finished yet... Ill start a new thread when its running.


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## Coulomb (Apr 22, 2009)

Nathan219 said:


> ... and use the IGBTs in parallel, to switch, which gets back to current sharing among power transistors.


Exactly: current sharing. MOSFETs tend to current share naturally; my understanding is that IGBTs don't. Then there is also the issue of getting them to turn on and off at exactly the same time.


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## jackbauer (Jan 12, 2008)

Read this :
http://www.evbmw.com/igbt.pdf


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## Nathan219 (May 18, 2010)

Thanks great article, explains the reason to mount the capacitors the way recommend to, to avoid stray inductance.


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## aeroscott (Jan 5, 2008)

thanks, that was great!


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## mbarber (Feb 18, 2010)

Nathan219

I have a bunch of new 100a Darling Transistior Modules that I'm dying to try to figure out a way to use in a controller, but I just dont have enough knowledge. I believe they are sufficiently similar to an IGBT that they might work for you. If you can use them and come up w/ a controller that would be great. If you are interested I can give you 10 of them for $25 to try out. If you are interested email me and I will send you the specs on them.
thanks


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