Not a big deal, I've been building current mode, fully protected supplies for, gosh, over a decade I suppose. A basic motor drive (the most basic to control, a PMDC machine I suppose) only takes an SMPS scaled up, making sure to add important protection features -- desat detector, overtemp, water flow (if water cooled), and anything else mechanical related.
To do a proper BLDC or induction drive (higher efficiency and power density), you need more phases (potentially many more, because you have the option of 3 (or more) level inverters), and you need a more refined control, usually something vector based. It could be basic PWM, but efficiency can be gained with more advanced adaptive/predictive methods to reduce rate of switching edges.
Make no mistake -- that one module is
at least a million dollars of engineering. Probably ten. Design would've started with breadboard prototypes, then design prototypes, then production prototypes, and finally production. When you're making a million of something, it doesn't even stop there: there is production engineering, from securing the supply chain, to the logistics of getting everything in, on time, every time.
There is absolutely, positively nothing impossible about this design -- I mean, obviously given it exists -- but it's clear, to me at least, where to begin and how to complete development of such a beast.
I'd love to do a design like that, myself; but I'm lacking some knowledge to do a comprehensive design, so some time would have to go to learning that; not to mention, the obvious and more pressing problem, that it would take me personally about ten man-years to finish the design! Part of the cost of these things is organizing a few dozen engineers to work on the various parts of it, so it can be completed in a reasonable time frame (maybe a year).
Related: when he showed the bus bar I said to myself, "that looks just like something Methode would make." Turns it over, see the sticker... hah.
Incidentally, it looks like that module uses just basic 3-phase 2-level inverters. Gate drive probably supplied by a many-output DC-DC converter, one of those gate drive controller ICs (like that ACPL-3xx I think) with external switches, and the switches are SOT-223 or TO-243 transistors at the gate terminals.
Regarding the IGBT modules, those didn't come out of nowhere -- they've been around for many years, I suppose originating with hybrid circuits going way back. Die bonded assemblies are 100% normal in industry, and if this isn't an off-the-shelf part, it's custom designed for GM (which is absolutely believable). I'm impressed by how many bond wires they needed, but, I mean, there you have it, that's what they need for that many amps.
Tim