openinverter forum

Hi Forum. As the last funding exercise for a 3D printer was such a success I was wondering if SDU owners (and those with defunct SDU inverters) would be willing to fund a Openinverter designed SDU replacement ? If enough of us agree would anyone be willing to take on the task? Would be great if we had a bespoke inverter that we could repair if the worst happened rather than shelling out another £1700+ should things go wrong. I am sure those who are now staring at an SDU 'paperweight' would be more than happy to contribute. Have we any takers for such an endeavor and if so could we agree a value for such a project? If a bespoke inverter as pcb and/or ready built were available for sale by the designer there could be a good source of extra income in it for someone with a web shop for instance The idea of having such an inverter would in effect close the loop for us and allow complete control of the electronic and electrical systems we use.

Firstly, I feel I should point out that Johannes already designed and published an open source inverter design (the original openinverter). It seems to have fallen into obscurity since OEM parts became the prevailing option.

I have actually been quite keen to design the inverter you want, but at 200kW power levels this is a fairly complex task. The main challenges will likely be the cost of parts (600A+ IGBTs and current sensors), and how to cool them effectively (designing a water cooling block).

Having already successfully designed and built a small induction motor inverter, I'd be more than happy to help work on such a thing, but I'm unclear how best to get started with it.

I think such a project will suffer from the fact that OEM parts are always likely to be cheaper and better designed

I very much marvel at Teslas original design and how much power they packed into this small unit. I'd say replicating that in the confined space is hopeless. Next up could be running the Tesla motor with an existing high power inverter like Ampera or Leaf.

Finally you could roll with the original openinverter design and build a relatively large external inverter with it. I found it to be quite robust as I used 400A/1200V IGBTs to run an induction motor at about 100A RMS. Quite sure pushing this towards rated IGBT current likely would have blown it. On the upside it didn't blow up when opening the DC switch on error

To add another dimension, while I was very amazed and humbled by the folks who have arranged and funded the 3d printer for me the fact remains that the vast majority of forum members did not contribute. I would guess the same would apply here.

I had a failed SDU inverter a few years back that I tried unsuccessfully to repair as it did not belong to me. Despite access to a laser welder and an operator I got nowhere. While designing and building an inverter from scratch is possible (I have done a few) keep in mind its not the electronics that will pose the problem but rather the hardware such as cooling, busbars, enclosure etc. What I would suggest is find a good cheap and powerful oem inverter like say the Toyota Camry in the US and let's design an openinverter board for that and use it with an SDU or any motor. Sure it's not as sexy as a bespoke design but when it blows just get another or keep another on the shelf.

I'm deep into reverse engineering the gate drive of the Model 3 inverter right now and while very nice its pure amateur hour compared to Toyota.

Anyway, just my 2c.

I think i may have one of the solutions. At least worth considering with broken SDU inverter.
I have sucessfully powered Leaf motor from ONE side of Ampera/Volt inverter. I went as high as 140kW draw from one side. Try to consider i used quite long 50mm2 phase cables.

1. Imagine to mount Volt inverter directly to SDU phase connections by short rails from the sides.

2. Imagine the upper option with connecting both sides of the inverter for true 200+kW.

I stil have some gen2 OI designed boards which have option to parallel both inverter sides. They are old design but they work. I can send them out if one wants to play and design a better board...