Effecient 3-Phase Buck PFC Rectification - Diodes out... Fets in?

[mobile_bob]

if you come up with a matching unit, you could parallel them by using a fuse for safety

connect both grounds together and then connect one positive to the other via a 1 or 2 amp fuse... if there is a parallel problem the fuse will blow before serious damage occurs.

generally..

i have used this method when in doubt

you might also have to isolate both units from each others, there may be issues with the cases connected in common, i don't know. again a small fuse might help to sort it out.

just a thought

bob g

[thomasonw]

It is interesting that I have been looking at these type of additions to alternators over the past few days.  And  I ran across this Masters paper where SRM was used in a standard 14v alternator (Most the work I had seen before concentrated on 42v deployments and used the SMRs in a boost-mode configuration to help fill in voltage dropping at lower alternator RPMs)  Seem much of the work for SMRs and Alternators came out of MIT in the early to mid 2000's - at least most of what I could find, though I did locate some Australian papers which looked to be durative work.

But this student concentrated on SMRs  and 14v alternators. And it included scheamtive and PIC code: http://dspace.mit.edu/handle/1721.1/46018

But even so, it is incomplete.  It does not do voltage regulation, and even though the word 'efficiency' is thrown around a lot - they are really talking about capacity.  Nowhere did they sample the 'efficiency' of the alternator (amount of mechanical work in vs. electrical output).  Over the past couple of days I have noted this seems to be a rather common error - people talk Efficiency, when really they are showing increased capacity, or total wattage out, of the alternator solution. . . . .

[mobile_bob]

in the white paper i presented here, i referenced efficiency and output

the output of the 555 alternator in its native voltage, is about 1900watts and approx
54% efficiency

when placed in the 24volt system, its output went up to 2880watts and very near 80% efficiency

i measure efficiency in grams of fuel consumed per kw/hr produced.

many of those papers don't go into the efficiency when they are focused on the switch mode rectifier, however there are companion papers, or full version papers where they also related the efficiency of the system as measured by power in vs power out.

i can't remember the two dude from mit, (durrault seems like one of the names) that did a lot of research into higher output and higher efficiency of standard automotive alternators,  i also see a few australian papers that look like carbon copies of the MIT work.   who did it first i don't know, and i didn't look into their references to see if either referenced the other in the work?  it really didn't matter to me who did it first, the concept or rather theory of operation was all i cared about.

bob g