Best way to control 150A Dc motor with Arduino

Other Hardware Motors, Mechanics, Power and CNC
1

Hi to all,

I would like to find out how to safely control two 1000W DC brushed motors with Arduino.
In particular, the DC motors are rated as 1000W, 50A, 24V, 2400 RPM.
Under load, in certain situations, they can draw also up to 150A for few seconds.

I have a radio transmitter system which has a receiver able to provide two outputs:

  • PWM in current mode (12V, 2A max)
    or
  • PWM in voltage mode (0-5V, 200 mA)

On the receiver, I have two outputs (one for each stick on the trasmitter).

I was thinking to use the PWM in voltage mode as input for two analog Arduino inputs and map them on two PWM arduino outputs.

The problem is: what is the best solution to control the high current? How to control each motor in both directions?
I also would like to set a maximum current limit (for example, 130A) for safety reason.

Should I use a 150A contactor, for example?

Thank you for all your suggestions!

2

How would you get the 150A contactor to switch at PWM rates?

Paul

3

Honestly, I'd look into a commercial motor controller. Something like this would be along the right lines. You'd probably also not want to run it right at it's spec, so maybe a 200A controller would be more suitable.

This could also work. Just attach your PWM output to the throttle.

I don't know how much that one sells for, but when I was part of the electric car team back in high school (2006 or something), they sold for $150-200.

The main reason that I suggest you use a commercial unit is in regards to safety. It would be possible to make your own, but i'm sure the price would not be terribly different (especially after you burn through loads of components to get there :p)

Matt

4

Or you could try something like a 4QD motor controller such as this. Either way, their website contains a host of useful motor control information.

5

The problem is that all the commercial solutions are able to control a single motor at time.

I need to mix the signals in order to achieve a tank steering driving style.

The motors are used to move tracks in a tracked vehicle.

Moreover, the output of my receiver provides 0-10V PWM output which is not compatible with most of the commercial controllers, I think :frowning:

I usually use Futaba receivers which offer a PWM outputs which work in this way:

1080 us -> the stick is going backward
1500 us -> the stick in the neutral position
1900 us -> the stick in going upwards

On the current receiver, the PWM output is 0-10V so I cannot detect if the motor should spin clockwise or counterclockwise..

6

That is normal, it is not the motor driver's job to be a motion controller.

7

MarkT:
That is normal, it is not the motor driver's job to be a motion controller.

There are solutions on the market that are able to control more than one motor at a time and, in addition, to provide additional functions but they are not suitable for my application since they are not IP6X and are too much expensive.

8

That is the price of industrial motion-control systems - which are always motion-controller plus
drivers (sometimes called amplifiers) for each motor. You'd install as many amps as you needed
for your motors upto the limit of the controller.

You have to be the motion control module now, without output signals for each motor channel.
Converting 10V PWM to 5V PWM is not difficult, even a resistor divider can do that. Mixing the
control signals (ie converting speed + steering to left + right) needs some some arithmetic after
detecting the pulse widths.

So break down the problem into:

  1. read receiver signal (hardware + pulseIn)
  2. combine/mix signals (if needed) to get separate drive levels for each motor
  3. convert drive levels (signed values) into PWM and direction signals for the motor drivers, if thats what they take.
  4. emergency stop. Don't ignore this with kW motors, provide both a hardware kill switch and software
    emergency stop signal, 1kW mechanical can maim and kill easily.
9

Yep. I was just going to say, throw a resistor in there to drop the voltage down to a suitable amount. V=IR :slight_smile:

Think of the motor controller as an extension of the physical motor. You will need to have one per motor (even in industrial applications that have multiple motor outputs, they will have separate individual motor controllers within the enclosure).

You're going to have a very hard time finding a motor controller to do exactly what you want. On the other hand, you can find a simple (dumb) motor controller and then write some code on a micro controller to give it commands.

10

So buy two of them (two motors = two controllers) and give them both the commands that you need to give them.

11

Yes, I'm planning to do this, but I'm not able to find single-channel controllers at a good price.

They are all above 600 euros.

I was looking for something between 250-300 euros since my current roboteq controller costs about 600 euros and allows the user to control two motors.

I would like to keep my budget below 600 euros for both controllers.

12

1kw is right in the middle of the range for electric bike controllers. I can't believe that you have to pay more than $100 per unit. I would expect to find bike controllers in the $40-$80 range.

13

MorganS:
1kw is right in the middle of the range for electric bike controllers. I can't believe that you have to pay more than $100 per unit. I would expect to find bike controllers in the $40-$80 range.

The most components for the bike controllers are from China (low quality) and they are for brushless motors.
It is not easy to find a good quality DC brushed motor controller.. :frowning:

14

Surely you mean "it's not easy to find a CHEAP but good quality DC brushed motor controller"

15

I

jackrae:
Surely you mean "it's not easy to find a CHEAP but good quality DC brushed motor controller"

I'm not looking for CHEAP devices, my budget is about 600 USD for both controllers.
I think this is a good price for a good device.

16

You will be able to find a decent brushed motor controller for $300 a piece. This one that I originally linked is only $120. Will this controller suit your needs, or am I missing something?

Matt

17

I already bought and tested them few months ago.
They worked fine on my testbench, but then I didn't tested them on a real situation since they are not good quality and the quality of the material is very low, unfortunately.

18

Here are some higher quality motor controllers. Unfortunately, it appears that they are going to be slightly out of your price range. You are dealing with a lot of power, and the components for that will be expensive.

19

rushlink:
Here are some higher quality motor controllers. Unfortunately, it appears that they are going to be slightly out of your price range. You are dealing with a lot of power, and the components for that will be expensive.

I already have these controllers, they are from Roboteq.