|
Fran had observed similar oscillation to what I had going on with a brushless DC motor he had done a couple years ago. He think's it's too hard of gate drive. Next time around I'm going to use either 15 Ohm or 22 Ohm or something like that The source at the driver and the source at the inside of the mosfet had a difference of probably a few volts. V = dI/dt*L. The L is pretty small, but the dI/dt was friggen ginormous. If I slow down dI/dt some, V is going to get smaller and it will keep the mosfet from going on/off/on/off.
Some igbts don't have this problem because of the Kelvin emitter connection, which has a separate path to the emitter inside the igbt from the power path.
|