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it will be a goer . the inverter could be hacked by replacing the control side , cheap in parts expensive in programing . as time goes buy we will be sharing / learning how to tune and write the software . I for instance am almost completely lost on programing , but it will come.

Blast from the past, well the Toyota HSD drivetrain to e-converison seems never happened. After all those years and millions of these hybrids sold (and god knows how much crashed/written off), strange and shall we say humbling..

You are right that one, probably the most straightforward approach is just to use the stock inverter as any other IGBT power stage/module on the market and replace/hook it up with own driving pcb (DSP) based on ARM cortex, which are pretty advanced these days and available ready-made in many flavors, under $500, some even with motor self-learning software routines etc. The other approach, leaving the inverter box intact and just hacking it layer above in the hybrid system ECU was a dead end, since you depend on the other stuff/systems in the car, which must be either left in state of confusion (error codes) - dangerous, or software replicated (faked) and/or physically transplanted from the hybrid donor, which is a bit pointless.

 

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Great to hear, that the transplant project is still alive, as you know, the inverter is heavily tweaked for their perm motors and hybrid pack (the inverter box includes VDC booster unit), so the closed loop might eventually be necessary, these hybrid motors have their own encoders/sensors build it, correct? In terms of output, are you going to be interested in exploring both options, since this is dual capable controller:

1/ running MG2 and MG1 at the same time (welded?)
2/ or just MG2 solo

The #2 could be used in RWD direct drive or tranny setups, picture MG2 shaft connected face-2-face with such tranny ala BMW/Miata etc., the rest of it like MG1 gutted out, (I noticed you are primarily exploring the "welded option" though)?

 

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On the encoder/resolver question - it might be worth exploring hookup with some pre-made box, which will digitize the analog input from resolver sensor into desired digi output feeding the inverter/dsp, resolver-2-digital pcb or such, someone-somewhere must have it, 12bit resolution should be enough..

Let me explain the #2, what it means is just powering the MG2, the planetary, MG1 and diff. are discarded. Yes you loose some "theoretical" torque and kW output gain from the #1 (welded scenario), but it will be much easier to get to work (and less weight), ~50kW not bad for donor-econoboxes, I know not that many in RWD around anymore. As I tend to think with the #1 option it won't be that trivial to set it up and run properly from the DSP point of view.