phase reversing only works with single phase. The most you can get with 3 phase is with svpwm (which reverses the phases as much as it can) AFAIK
i.e. a 300 volt battery with svpwm can create a 300x1.73 v peak to peak 3 phase.
aka 259 peak, which is 180vrms per phase. (not phase to phase), maybe 317v phase 2 phase rms (edit WRONG).
I ran some simulations using a 6 lead motor with each phase on a full bridge so each could be reversed completely, and it didn't help one bit compared to svpwm switching for a given battery voltage. SVPWM can also save on switching losses if you hold the lowest phase to ground (or the highest to the rail) and scale the other phases accordingly.
http://ethesis.nitrkl.ac.in/1133/1/C..._using_PWM.pdf figure 21.
maybe I made an error somewhere, but I'm pretty sure about this.
Edit: I lied, a 300v battery, using SVPWM can create 213v (line 2 line rms) 3 phase. It is the same for single phase (213v rms from 300v peak, aka 600v peak/peak with full bridge).