Mega2560 freeze with High Load on PWM FET

Other Hardware 3rd Party Boards
1

Hi,

I have standard Mega2560 MCU and 2 (two) power FET 250V 44A drived by PWM.

  1. FET High Voltage Supply is separate from arduino
  2. there is Diode across each motor contacts.
  3. FET driving by FET drivers (opto-isolated fast driver)
  4. PWM frequency is 16kHz

Everything works perfect as it should, until i have over-load at the one of the motors (around 100%-120% more then motor power, motor rating is 550W, issue usually ocuring at +/-1200W (calculated by current/voltage meters on the board)). So, since i have overload arduino freeze, and usually it still send PWM (so that's the problem and on-board window watch dog reset it), but still need to find out the reason why arduino freeze.

Was try:

  1. Use external +5V for arduino
  2. Grounded Cristal resonator surface
  3. I have decoupling on each input/output pins, power supply MCU pins - everywhere where it need to be.
  4. Software is not an issue - device have same effect with sketch with 4 lines....

Please help.

2

At the very least you'll need to tell us exactly what FET you're using, and show a schematic of how you have everything connected.