# What inside Zilla Controller



## noubal (Aug 25, 2009)

I've been hearing Zilla the most renowned DC controller.
Did anyone has the internal circuitry or had done some reverse engineering.
I'm very eager to know what IGBT are being used and how it is configured.

I'm sorry Othmar. I can't buy Zilla in my country.


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## EVComponents (Apr 20, 2009)

noubal said:


> I'm sorry Othmar. I can't buy Zilla in my country.


Why not? What country is it? 

We have shipped to many different countries in Europe, South America, Austraia, Canada, South Africa, Japan, Croatia (thanks Mate). 
I am not aware of any country that bans DC controllers.

Edit: I see that you live in Malaysia. What is it about your laws that prevent this?


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## noubal (Aug 25, 2009)

No restriction in Malaysia.
I hope to buy one soon.
By the way, what IGBT is being used in Zilla 1KV ?


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## racunniff (Jan 14, 2009)

noubal said:


> I've been hearing Zilla the most renowned DC controller.
> Did anyone has the internal circuitry or had done some reverse engineering.
> I'm very eager to know what IGBT are being used and how it is configured.
> 
> I'm sorry Othmar. I can't buy Zilla in my country.


Magic smoke. Don't let the magic smoke out, the controller will stop working.


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## EVComponents (Apr 20, 2009)

noubal said:


> By the way, what IGBT is being used in Zilla 1KV ?


The good ones.


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## noubal (Aug 25, 2009)

May magic be revealed, please mask magician.


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## KiwiEV (Jul 26, 2007)

racunniff said:


> Magic smoke. Don't let the magic smoke out, the controller will stop working.


I know this from experience.


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## ga2500ev (Apr 20, 2008)

Noubal,

You can learn almost everything you ever wanted to know about PWM motor controllers by reading M. Paul Holmes thread on homebrewing one here:

http://ecomodder.com/forum/showthread.php/paul-sabrinas-cheap-diy-144v-motor-controller-6404.html

Nearly 3000 posts over the last year and a half on the subject. JackBauer, who hangs out here has put one together using an IGBT module.

There's a wiki with a list of materials, schematics, and microcontroller code. Paul is also selling both parts kits and assembled controllers.

The Zilla just has really good engineering practice. Truthfully, from everything that I have learned of Tesseract, Paul, and JackBauer of the two or so years I've been here, I can outline the basic principles of IGBT PWM design.

1. Keep you PWM frequency down and drive the parts hard. Especially with surplus modules like the PowerEX CM600HA modules that you can find everyday on Ebay. Slow your PWM to 2 Khz or below. Yes it'll buzz, but it will work. The MIC4451 driver Paul uses here:

http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=576-1209-ND

Can drive up to 12A of current into the gates. This keeps the switching time down.

2. You have to have good current sensing and fast turn off if you overcurrent. Failing to do this is the fastest way to let out the magic smoke.

3. Derate, derate, derate, and derate again. As Lee Hart stated in an EVDL post (to paraphrase): when a manufacturer says that a IGBT can handle 600A of current, they are dreaming. Overengineer by derating to 1/3 of the rated values. So for those ever present CM600HA parts, don't expect to get over 200A continuous current through them. Now interestingly enough I've read a couple of application notes on parallel IGBTs, and they make the same observation. But they point out that you can get better current carrying capacity by paralleling and derating. So if you really needed 700A of continuous current, parallel 4 of the modules together and limit your current through them to 800A total, even though the nameplate states that you can get 2400A through them. It also seems to me that a smart move would be to current sense the current going through each of the paralleled IGBTs too and cut off early if the the current exceeds 1/2 or 2/3 of the rated current. The app note points out that temp, gate voltage, and a host of other parameters will cause IGBTs to unequally share current when paralleled. So that's why you derate the max current that each can carry.

4. Understand the purpose of the cap bank and freewheeling diodes. For the caps, ESR and ripple current are critical parameters. The key is to get enough of a cap bank to handle the changes in current movement as the switch goes on and off without burning up. Same for the diodes, because it protects your circuitry from the charged inductor when the switch turns off and so has to be able to handle the full voltage and motor current. Finally if you happen to use the diode in another IGBT for the freewheeling diode, be sure to tie the gate of that IGBT to a negative voltage (I think Qer or Tesseract said -8V) to ensure that IGBT never actually turns on.

I'd really like to see or put togehter a bolt together reference PWM controller implementation here. Use a cheap microcontroller, surplus IGBTs, and specify the proper caps and diodes to pull it off. It wouldn't be a Soliton1 or Zilla obviously, but a manageable controller that a DIY hobbyist could tackle.

ga2500ev


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