12V DC motor + driver, 50A peak, torque control resistor built in?

[MedievalMan]

I am constructing a HIL simulation platform for a custom built EPS system.

Assist Motor + Driver
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I need a 12V DC motor (brushed preferable), and driver/controller with up to 50-80A peak capability.

Now, I'm not that familiar with off-the-shelf products, but do any of the dc driver/controllers include a very small, precise resistor for current (torque) feedback? It would be nice if this were included in the package, but I'm just not sure if it's available. Perhaps there are other relatively simple built-in methods for current feedback.

Gearing
=======
I basically need a gearbox with about a 20:1 ratio to up the torque provided by this motor. Preferably, it would be 90 degree off-axis to connect to the output shaft. The literature on EPS sytems say that they use "worm shaft and reduction gears."

Any suggestions would be much appreciated!

Thanks.

Matt Lawson

 

[bklauba]

With many of the SCR and PWM, AC powered DC drives on the market (KB Electronics, Minarek, etc.) the current limiting feature is achieved by monitoring the voltage drop across a series resistor, typically a wire-wound, 5W - 10W, with a value that generates ~ 100 mVDC across the resistor at the current limit.

If your supply voltage is 12 VDC, you would have to go thru an inverter, but that is pretty easy, even at this power range. It also would allow you to chose from a wider selection of motors.

BK

 

[ScottyUK]

Explain a little more about your application and what you are trying to achieve without using industry jargon: EPS, HIL, etc. They probably have very different meanings in, say, the automotive world as compared to the electrical power generation world. Eng-Tips has a huge readership, and many of them don't have English as a first language (America and Australia, for example ). Abbreviations make things harder for the engineers from the non-English-speaking countries to contribute.

Remember the only things we know about your application and problem are the things you post here: be as full as you can be, and avoid abbreviations unless they are absolutely universal. Tell us why do you want a current feedback repeater signal, and why you are using a low voltage high current motor instead of the more standard industrial voltages, for example.

Hope you don't take this negatively, because it isn't intended to be such. Look forward to your next post.


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I don't suffer from insanity. I enjoy it...

 

[itsmoked]

Yes mr. sir, what r dah abbreviations mean?

As for your speed controller check the model RC aviation world as they have 60+ amp controllers that are smaller than match boxes and have all sorts of features.

 

[MedievalMan]

Thanks for your suggestion.

EPS=Electric Power Steering
HIL=Hardware-in-the-Loop.

Anyway, I'm basically doing torque (current) control for the assist motor. The only reason it's lower voltage, higher amperage, is because it's intended to simulate an automotive system.

I'm looking for a drive/control (though it doesn't have to have control built in) that has:

- 80A switching capability @ 12V
- built in current sensing (I really don't care how it's done... most use a very small series resistor.)

Thanks again,

Matt Lawson

 

[ScottyUK]

4QD in the UK have a fair range of LV controllers for your general type of application. I guess you'd have to provide your own control signal in to the unit, but I think you're already aware of that.

http://www.4qd.co.uk/

LEM have a vast range of current sensing devices from mA to kA, the majority of which require simple auxiliary circuitry (power supply etc) to provide an isolated current signal if your chosen drive doesn't provide a suitable output. They're fairly readily available from the usual component suppliers. The isolation afforded by these devices is well worth having - separating the heavy current from your controller is very rarely a bad thing.

http://www.lem.com

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I don't suffer from insanity. I enjoy it...