| ??? 08/22/08 13:36 Read: times |
#157663 - Some hints Responding to: ???'s previous message |
Your optos are unsuited. Don't use dual optos and don't use slowly 6N136 compatibles. Also, I miss the commonly used pull-ups at the outputs of optos. Yes, I know, there is something already in the IR21362, but these pull-ups/downs are not at all sufficient to guarantee fast switching times. So, I guess your switching times and propagation delays are >1µsec, which is way too much for driving IGBTs.
If you need to use optos at all, which is questionable in most applications, then use fast, single optos with adequately low pull-ups. Give the HCPL-2611 a try (which is a high performance 6N137 compatible) in combination with 1k pull-ups. From your scope plots I think there is too much distance between the IR21362 and the IGBTs, by the way. Kai |
| Topic | Author | Date |
| 3-phase Inverter IGBT phase waveform | 01/01/70 00:00 | |
| you are going to burn the motor | 01/01/70 00:00 | |
| Its a sine PWM | 01/01/70 00:00 | |
| ...or the IGBTs! | 01/01/70 00:00 | |
| i had same problem on a Hitachi 48kw inverter | 01/01/70 00:00 | |
| Gate Drive | 01/01/70 00:00 | |
| The driver cktry and the waveforms | 01/01/70 00:00 | |
| Bootstrap capacitors problems | 01/01/70 00:00 | |
| Some hints | 01/01/70 00:00 | |
| another interesting waveform | 01/01/70 00:00 | |
| No, no.... | 01/01/70 00:00 | |
Voltage rating of bootstrap capacitor | 01/01/70 00:00 |