Re: [TCML] IGBT paralleling

["Finn Hammer" <f-h@xxxx>]

Scott, all,


Since the concern of switching spikes has been mentioned in this thread, I  
would like to direct your attention to the "Predikter", a zero crossing  
prediction circuit of my own invention, which eliminates spikes due to the  
fact that it initiates the swiching before the zero crossing.
This means that, as the IGBT has stopped conducting at the zero crossing,  
the freewheling diodes don't have to conduct, and therefore also don't  
have to be forced into reverse recovery.
It is the brief shoot trough condition during forced reverse recovery of  
the freewheling diodes that chock excites the buss inductance, leading to  
fierce ringing of this intentionally high Q structure.

To learn more about the Predikter, read the thread at 4HV:
http://4hv.org/e107_plugins/forum/forum_viewtopic.php?68820

Cheers, Finn Hammer
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