Gen 3 DCDC Converter Troubleshooting

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LeonB
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Joined: Fri Mar 26, 2021 12:19 am
Location: Germany

Gen 3 DCDC Converter Troubleshooting

Post by LeonB »

I am running a v1d board in a gen 3 inverter (part nr. G9200-47230) and I have problems getting the 12V DCDC converter to work. I am very grateful for any hints on what could be the problem or what I could test further:

Using the buck boost to step down the 360V of the HV battery, I can measure ~200V on the low voltage bus. So that should be well within the operating range of the converter. Measuring the voltage between the +12V post and the inverter housing, I get a mere 0.1V. I tried both the delayed and non-delayed startup and there is definitely a 12V enable signal at the DCDC converter connector. When connecting a 12V battery to the converter, it is not charging/ no current is flowing. I run the openinverter board from a separate 12V battery, could this be a problem? Both batteries share the same GND, however, the DC sense measures the wrong battery voltage.

Another weird quirk is that I am measuring a pretty constant 116V between the 12V post and the HV battery GND. Connecting both through a 100ohm resistor lets the voltage drop down to zero. But after disconnecting the resistor, the voltage quickly jumps back to 116V. Should this not been happening because the converter is isolated? Do I perhaps have a broken DCDC converter?
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bexander
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Re: Gen 3 DCDC Converter Troubleshooting

Post by bexander »

To get the DC/DC to start there has to be a 12V battery connected to the DC/DC-output before startup.

There are some very high ohmic resistors (mega ohm) between HV and LV in the inverter, for voltage measurement. Probably the cause of the 116V. Should be ok.
LeonB
Posts: 55
Joined: Fri Mar 26, 2021 12:19 am
Location: Germany

Re: Gen 3 DCDC Converter Troubleshooting

Post by LeonB »

Thanks for your response:
bexander wrote: Mon Sep 27, 2021 5:00 am To get the DC/DC to start there has to be a 12V battery connected to the DC/DC-output before startup.
Unfortunately, after adding in the battery, I already tried the good old “turning it off and on again” without success.
However, I eventually connected the DCDC and openinverter board to the same battery and now it’s running just fine.
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