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High Current Control with s12x 
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LQFP144 - On Top Of The Game
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A buddy of mine asked if I knew of a way to control 0-50A running to a brushed DC motor, based on a 0-5V input signal.

Wouldn't that be as simple as using ADC input and a PWM output coupled to some HEAVY duty drivers?

Thanks,
Sean

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Tue Feb 10, 2009 5:47 pm
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It depends on what thier looking for. You mentioned PWM, so I'm assuming your looking for speed control? Perhaps your looking for torque control? If your looking for direction control or braking, you're looking for an H bridge. If your looking for speed control, or torque control, Microchip has a bunch of great documentation and source code. You might want to check them out.

Some notes beware the back-emf. Also I'm assuming your using MOSFET's or IGBT's to control the motor. If you are, avoid using multiple in pararelle (sp?) They tend to load down differently, such that one will handle most of the load, then pop. Try it with one switch if you can.

I know there are many open-source electric vehicle contollers. They handle large amp draws and motors. They'd be a great source of info as well.


Tue Feb 10, 2009 6:22 pm
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LQFP144 - On Top Of The Game
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Thanks, there's a lot of good info in your post!

Actually I need directional torque control. For THIS! http://www.gmtcny.com/eps.htm

Since they cannot work in a stand alone setup, I thought maybe a "simple" controller could be constructed.

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Tue Feb 10, 2009 6:29 pm
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Ah variable torque, w/ direction control. Perhaps over kill, but this may help you jump off the deep end. When i say overkill, I think your need less then 100W, this is 100KW, so more than you are looking for, however similar tech.

http://www.circuitcellar.com/archives/v ... mer/2.html

You can browse this article free of charge. I recall this article noted specific microchip sources, look at that they posted them as well. Here's a direct link to microchip.

http://ww1.microchip.com/downloads/en/D ... 70098A.pdf


Wed Feb 11, 2009 10:11 am
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LQFP144 - On Top Of The Game
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I like overkill :) Those high current circuits controlled via PWM or PIT should give decent torque control no?

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Fri Feb 13, 2009 6:05 pm
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Those 100KW units would cerntainly support decent torque, but the max torque is really dependant on the motor your driving. These bricks have fairly fast on and off times, so lower torque and fine control over torque should be obtainalbe, however they are several hundred a piece. So cost may come into play.


Fri Feb 13, 2009 6:24 pm
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I just thought about how over kill that really is. 1Kw should be fine :) 12vx50a is only 600w

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Fri Feb 13, 2009 8:13 pm
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