# Controller build for Ford Siemens Motor



## jhuebner (Apr 30, 2010)

Cool to see you got going.

Have you chosen your components yet? What voltage will you build for?

This should give you the idea:









What you (might) see is:


Large heatsink - this is vital. For higher power levels consider water cooling.
3 IGBT-modules mounted to the heatsink with a thin (!) layer of thermal paste
Bus bar : 2 strips of 15x2mm aluminum from the hardware store. Awesome power stages use more complicated setups. It depends largely on how close you come to the IGBTs maximum voltage. I run at 550V max with 1200V IGBTs so theres no need for optimization.
Snubber caps (the 3 white things). 1st step of optimization. Again it depends on the voltage/max voltage ratio whether you need em.
Main bus capacitors (the large round ones). I totally over-dimensioned these. They run up to 1100V and have a capacity of 840µF. If I were to build this power stage again I'd go for 700V/400µF. I discourage using elcaps. You will need ridiculously high capacity ratings to meet the ripple current capability that film caps offer. So they take ages to precharge.
Power electronics is easy if your components have some headroom.


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## Hollie Maea (Dec 9, 2009)

Thanks, Johannes. I haven't bought any of the other components yet--making sure that I get the right things. Here are basically what I am shooting for:

I want to have a 320V nominal bus. It seems like 600V IGBTs should be enough as long as I design decent busbars. As far as current goes, the jury is out on the burst capability of my motor. Most of the people who used this motor early on paired it with the (now unavailable) Siemens controller designed specifically for this motor. And the legendary Eric Tischer built his own controller, but his controller wasn't strong enough to push the limits of the motor (I think he was limited to 300A). It's rated at 67kw peak, but definitely it can do better than that. I'm pretty sure it can handle 400A for short periods. Anyway, I'd definitely be interested in any advice from anyone as to what size IGBTs I should get

As far as heat sinks go, I'm definitely wanting to go water cooled. My motor is water cooled, so I'll have a cooling loop anyway.

I asked Chris from Rinehart Motion Systems for advice on bus caps, and he recommended using these:
http://www.alliedelec.com/search/productdetail.aspx?SKU=70225844#tab=specs
I think I would have to have a very well designed system for them to be sufficient. I'm not quite the wizard that the guys down at RMS are, so I might want to oversize a little.

I probably won't buy any power stage components until I see if I have screwed up your kit


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## jhuebner (Apr 30, 2010)

Those caps look good. 100A ripple current capability is plenty.

I run the gate drivers with IGBTs that have 3000nC gate charge (Qg). That works fine. If you use modules with more than that you're into the unknown. Which doesn't mean it won't work


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## Hollie Maea (Dec 9, 2009)

Hopefully I didn't screw it up too badly:










Only thing missing so far is a resistor (r8). I probably dropped it on the floor or something. I'll have to just swing by radio shack.


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## jhuebner (Apr 30, 2010)

Doesn't look screwed up to me 

I just checked the part sheet against the auto-generated BOM. Seems like I forgot a 3.3k resistor. Sorry about that. The next kits will include it.


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