Brushless DC Motor Thermal Issues

[tomz0840]

Ok it has been a while. I have been finally able to get it to work. I’ve figured out that having all the ICs on one board makes it a lot simpler. It also made me buy components specifically for the project, so I knew what I was using (whereas before I just used components I had on hand, without knowing whether they were rated for the purpose (for example, I don’t know if the bootstrap capacitors were rated for 16V)). I also found the lowest RDS mosfets I could find (still low price), so I didnt have to worry about heatsinks which allowed me to make the components close together.

My next challenge will be change from Arduino to an STM32 (shouldn’t be too difficult, I understand the 6 phases of commutation), adding current sensing circuits (LTSpice simulated op amp circuit) and possibly adding some TVS diodes for ESD protection (if you have any suggestions for that, would be appreciated).

Again, thanks to everyone who helped me work on this project, really appreciate your help.

[APDahlen]

That’s great news, Tomaz!

I was thinking about you yesterday while working on this article Breadboard an H-bridge Motor Controller.

You have far surpassed my work.

Would you be willing to share your design and lessons learned with the DigiKey community?

Sincerely,

Aaron

[tomz0840]

Here is my design. I know it can be improved, but at this point I was just trying to get it to work at all with all the information I learned about gate drivers and the like. After running it for a dozen seconds it already gets very hot, even with a low RDSon of 0.47mΩ. But with the assumption it is running around 30-40-50A continuous, that would get make it around 0.5-1W which according to the datasheet would raise the temperature by 55C. Also the close proximity of the MOSFETs create more heat. I’ll do more testing and try to improve the board as much as I can.