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What is wrong with IGBT driver?
Posted: Tue Aug 11, 2020 8:26 am
by joromy
Can someone give me some hint on what could be wrong with my IGBT driver board?
With a ACIM Siemens at 50V, measured from phase to POS/NEG.
This is the OK IGBT output: (300RPM, 0.4Amp)
This is the faulty IGBT output, when i give moore throttle: (2-3kRPM, 2-3Amp)
I have tried to swap the driver board, and the fault follow the "fault" board.
Also tried to swap the PWR/PWM signal connector.
Re: What is wrong with IGBT driver?
Posted: Tue Aug 11, 2020 11:18 am
by johnspark
Just looking at the waveforms for the faulty IGBT output, i notice that the off signal has a pulse that has a smaller amplitude after each high signal. You can almost draw a ruler through the
The off signal has a second pulse signal that appears to not change.
Perhaps this means there are two unwanted things happening?
Also, i note that timing of the two pulses appears to be unchanged.
What happens if you adjust the PWM ratio?
Re: What is wrong with IGBT driver?
Posted: Tue Aug 11, 2020 12:33 pm
by joromy
The strange thing is that the "fault" is on POS and NEG, the driver has no common components for POS and NEG side?
The only thing that is common is GND and 5V PWR.
The scoop capture is still picture, in real time there it's more fault noise/peaks, when i put more power to the motor.
But if i put low power/RPM (300RPM, 0.4Amp) the waveform looks OK, just like the first scoop capture.
Re: What is wrong with IGBT driver? [SOLVED]
Posted: Tue Aug 11, 2020 3:23 pm
by joromy
Changed one of the the digital isolator, and now it's working