24VDC.....5A DC motor control

[rikotech8]

Hello. I have to design a simple DC controller. I am going to use PIC16F628's PWM peripheral. The code is the easiest part. I am the programmer. But when it comes to PCB design, I am not that rich. So till now two general questions comes up in my mind: What should be the PWM frequency? What should be the inductance of the choke (it depends on the frequency I guess)? May be some principal scheme would answer the most of my questions.
Thank u in advance!

 

[tusemo]

I did the similar project with LCD displaying the percentage of speed (actually pwm signal's ). I did the project with Pic16f877a, but all will be same except for pic's part.
Here is all project files (PCB designs, schematics, Program file in PicCCS C )
I hope this will be informative for you.

View attachment Mesut Turk.rar

 

[D.A.(Tony)Stewart]

PWM rate must be faster than commutation rate of the motor contact speed with Brushes but not too high that increases Eddy Current losses and not too low that causes audible noise. anything >20 kHz ought to be fine. I prefer twisted pair power wires to reduce inductive crosstalk noise and perhaps ferrite beads or better clamped ferrite shell around the pair, so you dont see any stray 1's and 0's to any input signals in your software. If you use 5kHz you can hear it on an AM radio. USe the lowest RdsON MOSFET's you can afford.

 

[tusemo]

The pdf versions of the projects are here..

 

[rikotech8]

Thank you both for the valuable information!