preventing mosfet burns..

[RoboDurden]

Successfully replaced two mosfets today :-/ Would be great for this firmware if it could be made safer (than other firmwares ?)

1. lose current phase cables: I learned (the hard way) that lose connections of one of the three phase current cables will make it more likely for the mosfets to burn ! Disconnecting hall cables do not seem to be a problem(?) I think the firmware could detect this if the current could be monitored at the same speed that the mosfet apply their pwm to different phases. So when the two mosfet of Phase A allow the most current but the measured current is less then "predicted", the board could/should shut down. The period of lesser current would identify which phase has a loose connection.

2. softer start/stop A few times already a mosfet bridge burned right at the beginning (and once at stop?), and there was not even any load/torque on the motor ! This time i reduced the DEFAULT_FILTER from 0.1 to 0.01 = 655. Such a slow start/stop is okay form my two circular saws on my log band saw: https://www.youtube.com/watch?v=sveUO8Rd1TQ But i feel that the start/stop could be somehow(?) made safer even for fast start/stop.

3. a safety help page ? Is there a wiki page on what other measures could be taken to prolong mosfet lives ?

4. hardware changes ? Does anyone had any success with hardware modifications ? Adding a protecting diode might interfere with the charge pump of the high-side mosfet :-/ Replacing the mosfets with better ones ? Simply soldering seconds mosfets on bottom of the existing ones might be easier!

Ideas welcome :-)