Arduino controlling voltage without PWM?

Other Hardware Motors, Mechanics, Power and CNC
1

I have an Arduino controlling DC motor with H-bridge motor controller successfully, using PWM. The output voltage goes from 0 to 19V, up to 2A.
However, it sees that some DC motors make more noise with PWM than with fixed voltage.
I also tried adding capacitors, but I can't use electrolytic because the voltage is changing directions from time to time.

Perhaps the best solution would be to control the output voltage, instead of using the frequency of the PWM?
Is there a simple solution that can be used?

2

yigalb:
The output voltage goes from 0 to 19V, up to 2A.

:o

PWM motor whine (if it's a problem) is commonly solved by using a PWM frequency outside our hearing range.
That's why computer CPU fans work with a PWM frequency of 25kHz.
Leo..

3

The Arduino Due has two analog output pins:

4

Wawa:
:o

PWM motor whine (if it's a problem) is commonly solved by using a PWM frequency outside our hearing range.
That's why computer CPU fans work with a PWM frequency of 25kHz.
Leo..

Thanks, this is a good idea, and I will check it with ESP32. I think it has much higher PWM frequency. I also have a Raspberry PI, should be good too.
But, I still want to consider the direct voltage control. The PWM method provides fixed voltage with duty cycle, which may works well for simple DC motor, but some toys like electrical trains use the tracks voltage also for some controls like small LCDs display, etc, in addition to run the DC motor.

So I would appreciate ideas for my original question: How to control the actual voltage with Arduino, not by PWM.

5

How to control the actual voltage with Arduino, not by PWM.

You need a DAC (digital to analog converter) to ouput a fixed voltage.

For a motor, you need a suitable controller. Most don't accept fixed voltages for control purposes.

6

With Arduino you can low-pass filter the PWM to smooth int into DC.
Then have to amplify the voltage with something that can properly drive the current needed for the motor(s).

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7

jremington:
You need a DAC (digital to analog converter) to ouput a fixed voltage.

That is why I provided link to Due, it has two analog output (DAC) pins:

8

Of course DAC will provide the ratio of the voltage. But is there a ready to go motor driver that can be used to drive the motor?

What I am actually looking for is a motor driver, that can be driven digitally (or by DAC) by the Arduino. Currently I am using LM298 motor driver, but this can either use PWM or output fix voltage (set by a jumper).

The LM298 has also 2 control signals that select the voltage direction or stop the operation, regardless of the PWM status.
So just DAC with amplifier will not do the job. Of course, everything can be designed from scratch, yet I hope there is an off the shelf solution.

9

Pololu has the best selection of DC motor drivers and DC motor controllers.