openinverter forum

I have played with gain and offset. I have -5v. I have triple checked the 50 pin under the microscope. When I connect 80V to the invertor there is no change in udc. Inverter does work and spin the motor during testing. I fear there is some thing wrong with the inverter.

Update I am losing -5 after installing board.

When in doubt, when you want people to help you troubleshoot, info dump.

Take clear pictures of your setup.

Show your settings.

I think some thing is going on with ic17 with the 2276. It doesn't start when every thing is pugged in but works when everything is unplugged. I have hvil bridged but I don't believe its used anyway? I built the wrong board for my inverter so it is missing 2 screws and a ground screw near the ic17.

Again, look at the amount of info you've shared, and put yourself in the shoes of someone troubleshooting for you. Could you have troubleshot a similar task with that small of information?

I don't know how to solve your problem, but I can only imagine that the people able to do this, their first question is going to be that you provide them more info.

Should I have -5v with every thing hooked up?

Looks like you have wrong udcgain and udcoffset. I propose to start with its default values. And be more verbose on your test conditions. Eg we see 664V udc, but have no information about the physical voltage.

Sorry 0v connected. I will recalibrate and report back.

.

udcgain 5 and udcofs 0 Default from wiki I get udc resting at 133v with 0v or 80v connected to the hv no change on plot during precharge. Is 80v too low?

Looks like a hardware issue in the measuring circuit. Maybe a broken connection on the ADC pin or a shortcut to an other signal. I'd expect that 0V HV is shown as nearly 0, and 80V is shown as nearly 80V. Maybe with some tolerances of +/5V.

I had a lot of problems with my PCB from jlc. I had a failed capacitor and resistor on 26v line so far so I’m not surprised. I will look through the schematics again thanks for the input.

Most likely culprit is the 50 pin connector, I'd check it a fourth time, the specific pin. It was a dry joint on my single board with UDC not working

Will do.Thank you everyone for your help. The lm2776 let the smoke out during yesterday’s test. I’m waiting on a replacement. I’m going through the caps and I will check the 50 pin one more time. I’m just glad the inverter outputs pwm.

If the lm2776 smoked, there is more wrong. You should check its input voltage, and how much current is on the negative rail which the lm2776 should produce. Can be done with a lab power supply.

could not find my nice power supply. So I improvised with one of my chargers. I'm happy to report the udc reads correctly when supplying the -5v from the power supply. Current was set to .050 ma. Thinking it was a defective 2776. Thank you uhi22 ! Great idea with the power supply.