I enjoyed that video but it also confused me a bit. It is useful in that it clearly makes the point that what's different about the PSD is that, unlike the planetary gear system in the Ford Model T and many others, at no time is any of the three components ever locked or fixed. The sun-gear, planetary gears, and ring gear are always free to rotate, and do.

What was not clear to me was the power flow from the ICE to the wheels. It seemed as if he was saying that the only connection from the ICE to the wheels was indirect, by turning MG1 to generate current that could drive MG2 which drives the wheels. But I don't think that's the case.

I know that if I floor the pedal entering the freeway, the ICE spools up to something like 5000rpm and holds there while the car accelerates. So clearly there is a flexible connection. But is all of that mighty horsepower being transmitted by first being turned into AC in MG1, which flows to MG2, which turns it back into torque? Because that would be rather inefficient I would think.