What do you folks think about application of three-level boost converter in PFC?
Three-level boost converter in PFC vs. conducted EMI
It seems very compelling for me, rather for multivoltage input then for real PFC in three-phase power supply.
Both (+) and (-) of the DC bus are HF switching potentials in relation to input lines.
That is because there are diodes on both (+) and (-) lines.
It means that the number of elements and conductors with fast voltage transitions is increased.
Obviously there will be isolated DC/DC converter/converters after this non-insulated boost.
I predict increased problems with CM noise. Another problem is that I want to have entire control of DC-DC converter on protective earth potential. Of course drivers of switches in the converter are insulated, but then they're exposed to additional voltage transitions from PFC. On the other hand, since there are only n-channel devices, in DC-DC converters only those switches with emitter/source connected to (-) are free of this disadvantage. I have never noticed any problems with any false operation of isolated floating switch driver.
Am I exaggerating with my afraids?