# Re: [EVDL] Home-Made Simple IGBT based DC motor controller



## EVDL List (Jul 27, 2007)

*Re: [EVDL] Home-Made Simple IGBT based DC motor controller*

You need to do more research on motor controllers.
Look at the application notes for the IGBT modules.
Jack


> --- paul holmes <[email protected]> wrote:
> 
> >
> > I am getting 8 IGBT's (1200v, 600a, 4100watts each).
> ...


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## EVDL List (Jul 27, 2007)

*Re: [EVDL] Home-Made Simple IGBT based DC motor controller*



> paul holmes wrote:
> > I am getting 8 IGBT's (1200v, 600a, 4100watts each). Does anyone see
> > potential problems from replacing the power mosfet in the following simple
> > 555 based PWM controller with the 8 IGBT's in parallel, which should be able
> ...


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## EVDL List (Jul 27, 2007)

*Re: [EVDL] Home-Made Simple IGBT based DC motor controller*

That is bizarre! Here's a couple more questions. First, where is the EV
tech list? That sounds like a nice place to post this sort of stuff. 
Second, Since it's an isolated gate device, and the leakage current from
gate to emitter is about 0.5 microAmps (when the device is conducting from
collector to emitter, as far as I can tell from the IGBT documentation), why
can't the 555 deliver 4 microAmps (8*0.5)? Can't it put out 200milliAmps? 
I could see that signal cleanup would be important, though. I hadn't
thought about that before.

-Paul

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## EVDL List (Jul 27, 2007)

*Re: [EVDL] Home-Made Simple IGBT based DC motor controller*

From: paul holmes
> I am getting 8 IGBT's (1200v, 600a, 4100watts each).

Ah, the fun is about to begin!  I suggest derating them about 3:1 i.e. if it's a 1200v 600a rated part, don't use it over 400v 200a nominal. This allows for voltage transients and real-world heatsinking. Those published ratings are absolute maximums that can't be achieved in real life.

> Does anyone see potential problems from replacing the power MOSFET in
> the following simple 555 based PWM controller with the 8 IGBT's in
> parallel, which should be able to handle 32.8kWatts continuous?

This is an excessively simple circuit. It has left out so many parts that it would barely function. Trying to use it for a high power controller would be a disaster.

> And if there are problems, which I'm sure there are, are there
> any suggestions for improvement?

- Don't parallel IGBTs. It's hard to do right for a first-time builder.
- Add a freewheel diode across the motor (can be one of your IGBT
modules used as a diode).
- Forget the 555. Use a switchmode power supply chip (of which there
are hundreds). Pick one with current limiting, internal regulator,
undervoltage protection, higher output drive current, etc.
- Add a gate driver circuit. You need at least 10x more gate drive
current than a 555 timer can supply.
- Add a shunt to sense current, an amplifier, and use the resulting
signal to control the PWM chip.
- Sense IGBT temperature, and use it to limit or shut down the
controller.
- Add open or shorted speed control pot failure shutdown.
- Add a robust power supply for the logic.
- Add a large bank of filter capacitors across the battery input.

This should get you started. Good luck!


--
Those who say it cannot be done should not interrupt the one who is
doing it. -- Chinese proverb
--
Lee A. Hart, 814 8th Ave N, Sartell MN 56377, leeahart-at-earthlink.net

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## EVDL List (Jul 27, 2007)

*Re: [EVDL] Home-Made Simple IGBT based DC motor controller*

Hi Paul,

The 0.5 microAmps is the static DC leakage. In operation the AC 
characteristics will dictate the drive current requirements because the IGBT or MOSFET 
gate is a capacitive load. Additionally, the drive circuit must be able to sink 
the miller currents generated by the gate to drain capacitance in a controlled 
manner.
This question is directly answered in an International Rectifier application 
note # AN-944. It is a PDF file that can be downloaded here: 
_http://www.irf.com/technical-info/appnotes/an-944.pdf_ 
(http://www.irf.com/technical-info/appnotes/an-944.pdf) .

Hope that helps!

Ken



In a message dated 3/29/2008 3:46:26 PM Central Daylight Time, 
[email protected] writes:

That is bizarre! Here's a couple more questions. First, where is the EV
tech list? That sounds like a nice place to post this sort of stuff. 
Second, Since it's an isolated gate device, and the leakage current from
gate to emitter is about 0.5 microAmps (when the device is conducting from
collector to emitter, as far as I can tell from the IGBT documentation), why
can't the 555 deliver 4 microAmps (8*0.5)? Can't it put out 200milliAmps? 
I could see that signal cleanup would be important, though. I hadn't
thought about that before.

-Paul



**************Create a Home Theater Like the Pros. Watch the video on AOL 
Home. 
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## EVDL List (Jul 27, 2007)

*Re: [EVDL] Home-Made Simple IGBT based DC motor controller*



> Lee Hart wrote:
> >
> >
> > - Don't parallel IGBTs. It's hard to do right for a first-time builder.
> ...


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## EVDL List (Jul 27, 2007)

*Re: [EVDL] Home-Made Simple IGBT based DC motor controller*

> First, where is the EV tech list? 

Evtech mailing list
[email protected]
http://mailman.evtech.org/mailman/listinfo/evtech



Rush
Tucson, AZ
2000 Insight, 66.7lmpg, #4965
www.ironandwood.org
www.Airphibian.com
www.TEVA2.com



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## EVDL List (Jul 27, 2007)

*Re: [EVDL] Home-Made Simple IGBT based DC motor controller*

Here's a 50 volt, 110amp(draw), 5,500 watt controller to play with:

http://www.castlecreations.com/products/phoenix_hv_series.html

25v, 180a, 4500w

http://www.castlecreations.com/products/phoenix-180.html

Brushless though. What happens when it's hooked up to a brushed motor?

Why can't it be scaled to 600 or 1200 volts and ludicrous amps?

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## EVDL List (Jul 27, 2007)

*Re: [EVDL] Home-Made Simple IGBT based DC motor controller*

> Each IGBT has a power rating of only 4.1kW. My EV is already going to be
> really wimpy. 

Perhaps you are confusing the power dissipation rating of the IGBT with how
much power it can *deliver*. The beauty of PWM is the the transistor spends
most of its time fully on (relatively low power dissipation) or fully off
(no power dissipation?). The transitions between these states are what you
want to keep to a minimum by sizing the drive circuitry appropriately. If
you can achieve 90% efficiency then in theory a single IGBT will deliver
almost 37kW (50HP) to your load.

Steve


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## EVDL List (Jul 27, 2007)

*Re: [EVDL] Home-Made Simple IGBT based DC motor controller*

>
> Uh Oh. That's not good. How on earth do I get the 40 peak HP that I'm
> wanting for my EV conversion? (other than starting over with a bunch of
> MOSFETS)

I'm confused. Are you concerned about cost?
If so why on earth are you building you own controller, that almost always
ends up costing more (sometimes far more) than buying a commercially built
controller.
Even if you don't let the smoke out of a few sets of power silicon, buying
all of the necessary components to build a controller will cost as much as
and assembled one.



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## EVDL List (Jul 27, 2007)

*Re: [EVDL] Home-Made Simple IGBT based DC motor controller*



> Peter VanDerWal wrote:
> >
> > I'm confused. Are you concerned about cost?
> > If so why on earth are you building you own controller, that almost always
> ...


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## EVDL List (Jul 27, 2007)

*Re: [EVDL] Home-Made Simple IGBT based DC motor controller*

>
>
>


> > Peter VanDerWal wrote:
> >>
> >> I'm confused. Are you concerned about cost?
> >> If so why on earth are you building you own controller, that almost
> ...


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## EVDL List (Jul 27, 2007)

*Re: [EVDL] Home-Made Simple IGBT based DC motor controller*


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