0
\$\begingroup\$

I would like to find out the best solution to safely control two 1000W DC brushed motors by using a atmega328p. In particular, the DC motors are rated: 1000W, 50A, 24V, 2400 RPM.

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

  • PWM in current mode (12V, 2A max)

or/and

  • PWM in voltage mode (0-5V, 200 mA)

Each output on the receiver is triggered by a proportional stick on the transmitter.

I was thinking to use the PWM output in voltage mode as input for two analog atmega328p inputs and then use these values to control two PWM outputs on the atmega.

The problem is:

what is the best solution to control and switch the high current?

How to control each motor in both directions?

I also would like to set a maximum current limit (for example, 100A) for safety reasons.

Should I use 100A-rated contactors, for example?

May be, relays are too slow..

Thank you for all your suggestions!

\$\endgroup\$
  • 1
    \$\begingroup\$ Contactors and relays are not suitable for PWM or variable-speed control. A 100A motor controller with MOSFETs is doable with careful design (heatsinking and gate drivers), although I wouldn't reccomend it as a first electronics project. \$\endgroup\$ – pjc50 Jan 13 '17 at 20:52
1
\$\begingroup\$

Should I use 100A-rated contactors, for example?

May be, relays are too slow..

Depends on what you want to use them for!

Relays would be sort of "ghetto-rigging" it, but if thats fine for the application then go for it. If you're going to be switching them on and off a lot (with PWM or something) a solid-state relay would be worth the extra money.

That being said, just get an off the shelf motor controller for 1000W DC brushed motors. It will make your life much simpler.

| improve this answer | |
\$\endgroup\$
  • \$\begingroup\$ The problem is that off the shelf controllers are not very customizable. Moreover, if I can use solid-state relays or contactors it should be safe.. I need to switch them on and off lots of times. The motors move a skid steering tracked vehicle. \$\endgroup\$ – Marcus Barnet Jan 13 '17 at 21:01
  • \$\begingroup\$ Every solution will be some sort of compromise between customizability and simplicity. You'll just need to choose the one that fits your needs. \$\endgroup\$ – GandhiGandhi Jan 13 '17 at 21:36
0
\$\begingroup\$

There are plenty of suitable H-Bridge PWM controllers from the RC community. Here is a link to a more professional dual channel unit by RoboteQ that might fit your requirements (they even show you how to connect all your safety wiring).

Whatever you select, be sure to get a unit that handles more current than your motor requires as you may have peaks over the rated current (run into objects and stall current). I'd suggest that 100A would be a reasonable selection.

There are also plenty of much cheaper RC PWM ESC controllers that handle 50-100 A, but definitely more hobby type reliability. Just search for "RC PWM ESC 100A"

| improve this answer | |
\$\endgroup\$
  • \$\begingroup\$ I already use roboteq controllers for these motors, in particular, the HDC2450, and I know them very well :) the problem is that roboteq controllers work well with RC PWM inputs (1000,1500,2000us) but they will have problems with my 0-10V. I need to process the PWM signals since I need to mix them for tank steering. \$\endgroup\$ – Marcus Barnet Jan 13 '17 at 21:59
  • \$\begingroup\$ There are plenty of safety reasons not to casually do this on a system of the size you seem to be contemplating. But from a theoretical standpoint, you can process PWM inputs to generate PWM outputs, though you may incur a frame or two of delay. It might better however to do your mixing at the transmitter. Also, note that you cannot mix a single stick to tank steering, unless you put a break in the control mapping, ban rotation-in-place, or accept flipped steering when going backwards. \$\endgroup\$ – Chris Stratton Jan 14 '17 at 7:56

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.