I’m trying to wrap my head around the differences between spwm and svpwm for foc, my setup currently does not have current sensing nor back EMF readings, so i will need to do position control with only the absolute encoder position, my question is the difference between spwm and svpwm for this kind of control, what measurements can i make to compare the effience of these two methods?
As I understand it, SVPWM gives you 15% more usable voltage with no drawback whatsoever, aside from a few CPU cycles to calculate the offset, and the more intuitive nature of SinePWM for beginners. The voltage difference between phases at any instant is the same as with SinePWM, so the current waveform is unchanged. The voltage waveform just doesn’t saturate as soon.
There are a variety of voltage waveforms that could accomplish the same thing (e.g. having a flat peak instead of the bump-bump of SVPWM, and pushing the other phases down by the amount the flattened one would have gone up if it were a sine wave), but the points of maximum voltage difference would be the same so there’s nothing more to be gained.
TL;DR: Just use SVPWM. It’s better, and there’s not much to compare between the two.