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Ever see a PWM technique where the 2 triangle wave are used; + & – (inverted), each goes to a separate comparator and the error input goes to both comparators, with a common reference (so both triangle waves trip their respective comparators simultaneous, to make the ‘T’ (totem-Pole) amplifier outputs switch in a way that if the error voltage matches the reference voltage, both amplifiers outputs go high and low, in unison, i.e., remain in dynamic brake mode high side, low side, high side, low side, etc., 50% duty cycle. If the error goes above the reference, the Amp A is +++_+++_+++ and Amp B is: _+__+__+_ A.hi.B.lo, hi.side.brk, A.hi.B.lo, lo.side.brk, A.hi.B.lo, hi.side.brk, A.hi.B.lo, lo.side.brk; you get the idea. Not lock antiphase, kinda modified sign magnitude. Limp for position servo. Seems bad, but is real; is in use. Comments?
This is an interesting way of deriving the wave-forms. I haven’t seen it done exactly as you’ve mentioned here. If I understand what you are doing, I describe something very similar here: http://modularcircuits.tantosonline.com/blog/articles/h-bridge-secrets/h-bridge-control/ (look for complex drive modes and heat-spreading). There is a difference in your control signals in that they more resemble lock-anti-phase drive than sign-magnitude drive. Your motor control however is sign-magnitude drive like. There might be a problem in generating the opposing ramps, but other then that I think it’s a rather clever approach.