Syncronous rectification of three phase is a daunting task , but admirable.
i too was thinking of sync rectifing an alt, because as you say , diode losses can be excessive at high power.
the problem as i see it , can be broken down to sync rectifing each phase seperatly, which implies three seperate circuits.
i tried doing just that , sync rectifing a single phase , as a starting point .
i used the wave itself to drive the gates of four Fets , in an H pattern with cris crossing gate connections , maybe it was the breadboard connections that was giving me problems , i dont know.
anyway it came down to switching , the gates , of two fets at a time , to produce a rectified sine wave
and since you would be switching them when current flow is at its minimum , zero crossing, there is little chance of spikes across the fets, and since voltage leads current in an inductive circuit , knowing the inductance of your alt may prove benificial.
but combining the three outputs , without using diodes , only complicates the body diode problem, to a point that i finally gave up on the idea.
in the end i figure that a little loss at the beginning is better than a non workable circuit at the end
, for me anyway.
and have decided to concentrate my efforts to using pwm , in a little boost circuit that i'm going to try tonight , as i am about to wind a 91.9uH inductor , air core .
i set the parameters to output 24A into a 24V battery , nothing spectacular ,but if all goes well , who knows
this should be interesting , i just realized that i cant measure 24A yet , but i have a few analog ammeter gauges that just need the proper shunt.
hi ho , hi ho
