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Old 10-21-2015, 05:46 PM   #2215 (permalink)
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Originally Posted by thingstodo View Post
As for currents - V*I into your controller = V*I out of your controller, so if your input voltage is 100VDC and your output voltage is 7.17VAC (10 VDC peak to peak as an RMS value) then your current is 10X more on the output than on the input. That's one of the beautiful things about low ESR Capacitors as energy sources. Coulomb counting helps - you can't get more out of the capacitor than it can hold .. unless you count the charging current that the capacitor receives as the output voltage drops.

The currents through the diodes .. normal for IGBT on, but should relate to the energy stored by the motor's magnetic field, as it collapses when the IGBT turns off. The amount of time to collapse the field, and how the series resistance is split up in your model would likely have a large effect on the magnitude.

If you have anything in particular you'd like me to check during testing - a diagram helps. I have several uncalibrated 50A 100mV shunts, a clampon meter, 2 channel scope ... a couple of cheap multi-meters .. and I can take video of the measurements.
Here is the crux of the problem and my distrust of the model.

Yes - energy in should = energy out. Otherwise, I have a perpetual motion machine! Woo Woo! Ummmm, off to the Unicorn corral with me.....

I think what I'm seeing is a lot of current going around in circles between the motor and the inverter. As you've said, the collapsing magnetic field should severely limit this. Right now, I'm using a simple inductor for a motor winding. Perhaps I should use some form of loaded transformer instead?

Regarding testing - have you done some locked rotor tests, where you measured the current in the motor phases and the battery? ORNL did test like this. Hmmm - I'm going to look - maybe they have some raw data.

Thanks again,
- E*clipse
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