openinverter forum

Because I'm a tight-wad I'm wondering if it's possible to use the same Gen 3 inverter as a charger and inverter? This could save a fair bit of space, potentially and maybe cut down on cabling etc?

Possible, impossible, clever, stupid?

Yes viewtopic.php?f=14&t=257

I noticed that post, but for me, it wasn't clear if they are using the inverter to control the motor AS WELL AS using it for a charger?

Gen 3 has two inverters in its housing for MG1 and MG2. In cases where only one motor is used MG2 inverter is used for the motor and MG1 can be used as a charger.

Ah, see now you've got me wondering...

A single open-source unit for inverter+charger+dc/dc might possibly work on my bike.
Especially as Curtis still haven't bothered to call me back yet...

What voltage do these things work down to?

clanger9 wrote: ↑Thu Mar 26, 2020 1:37 pm A single open-source unit for inverter+charger+dc/dc might possibly work on my bike.

I have very similar ambitions.

clanger9 wrote: ↑Thu Mar 26, 2020 1:37 pm What voltage do these things work down to?

Damien has done many inverter / motor tests at 12V. I've messed about with one running a 24V motor...
The control logic needs a clean 12V however the power / motor side of the converters can be anything within the voltage and current limits of the power output transistors.

However the 12V DC/DC converter can be sensitive to the input voltage. I've done some work on it but only in relation to fooling it to work on a higher than designed voltage.

clanger9 wrote: ↑Thu Mar 26, 2020 1:37 pm Ah, see now you've got me wondering...

A single open-source unit for inverter+charger+dc/dc might possibly work on my bike.
Especially as Curtis still haven't bothered to call me back yet...

What voltage do these things work down to?

I managed to get DCDC to work from 100Vdc up to 310Vdc. It can output like 1kW 14V before it drops voltage.
viewtopic.php?f=14&t=51&start=50#p948

My version of EMW - Prius charger interface works on bench. I still have to sort the transistor control here since it sort of stalls on charge command. I am sure it is a problem with PNP/NPN transistor orientation.
Right now i am working on dual motor Volt inverter drive while also developing single motor drive from both sides in parallel. This is taking its toll on my time, so charger is no. 3 priority. Should have it back on dissection by next month.

Wow, had no idea they'd go that low! Great to hear the DC:DC is happy down to 100V without modification (though I only need 100W, not 1kW!). If it'll handle ~350A (@128V) on the motor inverter then this could well work for me. Then it's just a case of hacking around with the second inverter to use it as a battery charger. Single, cheap unit and cooling system =
Power factor when charging will be horrible, but that's a separate problem.

Step 1: make a cardboard mockup of the Gen 3 unit and find out if it'll fit anywhere...

clanger9 wrote: ↑Thu Mar 26, 2020 5:28 pm Power factor when charging will be horrible, but that's a separate problem.

I am sure it will handle 350A no problem.

Well power factor from single phase is attrocious, maybe 65% efficiency there. However i use my charger from 3phase and here PF is not an issue since phase shift is the same on all three phases.
At 600V buck to 100Vdc Transistor will suffer though and you will probably have to see how to handle the heat buildup.
Or you could use 150V....

EDIT: I would recommend at least 120Vdc with DCDC 12V stage. When i tested it at 100Vdc voltage was down to 13V.

Thank you! Current plan is for a 32s battery pack (so ~128V). I can probably get away with horrible power factor for home charging on single phase; being able to charge at a decent rate on 3ph AC public chargers would be amazing.

What are the approximate overall dimensions of a Gen 3 inverter?

clanger9 wrote: ↑Thu Mar 26, 2020 7:47 pmWhat are the approximate overall dimensions of a Gen 3 inverter?

Something around 14"x14"x8"?

Maybe 16"x16"x10"?

Between toaster size and microwave size.

That's close enough for me!

i am going to use gen 3 inverter for my two motors, and a gen 2 inverter for battery charging, and possibly single or 3 phase output for house battery backup later on. I have got permission from my mechanical engineer CPENG to install a gen 2 inverter where the muffler smoke box used to be on my e39.