openinverter forum

Hi,
my name is Karl and I am completly new to this! I'm an automotive Engineer with 30plus years of experience with ICEs /(. Now I started my EV journey with a little Gem. It is a Audi A2 Prototype from a company in Germany which was converted 13 Years ago with a synchronous 50Kw Motor and a Control techniques SP43.. industrial Inverter. The complete coversion is a part of automotive history and meanwhile shacked down well . The Inverter and the none automotive cableing are showing severe signs of wear and Problems occure meanwhile on a daily basis.
I would like to exchange the industrial inverter (I have a good use for it in a Haas CNC Milling Machine ) against a current automotive one. I'm focussing on this beautifull Open-Inverter Project!
Since the current system has a well working Zebra Z37 Battery I would like to keep using it. BUT! It is a 620V/ 38 Ah Salt Battery... Now, after reading for only a few days I have a question regarding the Inverter Voltage. I hope that I understand correctly, that the Prius Gen 3 Inverter can handle up to 650 V after the boost converter with a 200+ V Batterie of a Prius attached before the converter. Can I connect a 620V Battery to this kind of Inverter? And what changes would have to be made to the Inverter if possible.
I will post some pcs soon.
Thanks
Karl

If you connect as shown in the wiki, this by-passes the boost converter ( You can use it in reverse as a buck converter to get your 620V down to 200 ish for the DCDC). The main cap of the Prius inverter is rated at 650V. Start a project thread with your progress and photos

The prius (gen 3) inverters have a 750v caps (on the motor side), the auris/yaris inverters have 650v caps (i think the later gen4's have a 650v cap also but have only had apart a yaris & gen 3 prius inverter )
tbh we dont make much use of the HV dcdc in the prius unless your running the 12v dcdc.
whats your fully charged voltage? as you dont want to exceed the voltage rating on the cap.

Hi,
thanks for your quick replys! Sounds promising! The fully charged voltage is 648V, which is close to the specs of the Auris Inverter as you mentioned. Is it too close? Is it possible to exchange the caps if needed? Maybe a silly question, but I have the Auris Inverter.... To buy a Prius one isn't hard as well;-)
Second question is: The Voltage can drop to 420V / 30sec peak power. What will that effect without the boost connverter in the loop? I assume, that this will happen in the original Prius supply as well. But will the boost converter smooth that out?

The current control loops of FOC will take care of the voltage drop.
The boost/buck converter is too weak for drive power anyway, it will just drop your 600V to 200-ish V if you wish to use the 12V DC-DC converter

Ok, very informativ and- again- promising! Many Thanks for the support.

DonKarlos wrote: ↑Tue Sep 26, 2023 10:38 am Hi,
thanks for your quick replys! Sounds promising! The fully charged voltage is 648V, which is close to the specs of the Auris Inverter as you mentioned. Is it too close? Is it possible to exchange the caps if needed? Maybe a silly question, but I have the Auris Inverter.... To buy a Prius one isn't hard as well;-)
Second question is: The Voltage can drop to 420V / 30sec peak power. What will that effect without the boost connverter in the loop? I assume, that this will happen in the original Prius supply as well. But will the boost converter smooth that out?

That would be too high voltage IMO for the capacitor to handle, there must always be some overhead, if you can get the 750v version then you have on paper a good safety margin. capacitor breakdown can occur due to temperature so something that may work fine when tested could fail when under heavy load / heat soak and could fail when you need it most.
Exchanging the caps would be possible with the older gen 1 inverter, but the new ones use custom design film caps that are integrated into the inverter.

for general reading the 2010 gen3 prius inverter tear doen by oak ridge national lab....
https://info.ornl.gov/sites/publication ... b26762.pdf

This is a very comprehensive Information about the 2010 Prius Inverter, which makes it mandatory to switch from the Auris Inverter (at least the G9200-52031- former Inverters of the Auris are maybe diferent) to a Prius Inverter with the large Capacitor pack in the Top (probably the G9200-47140). That way, as stated in the report, the Inverter system should be compatible to 650V Battery out of the box with connection of the HV Battery behind the Converter. I will got that route.
Thanks for your initial support!