T
treez
Guest
Hello,
We are using a 3.3kw Brusa NLG514 electric car battery charger (Air-cooled, mains powered). We dropped it many times and thought something was loose inside, so opened it up.
We saw absolutely no electrolytic capacitors at all!
Brusa NLG514 charger.
**broken link removed**
There were two separate film capacitor banks of about 6uF each, that was it!!
The power transformer was potted into the corner so we could not see it. (~65mmby65mmby45mm)
We saw two torroids in one of the side panels which we assumed must be boost PFC inductors but dont know because they are sandwiched inside two panels.
Surely electrolytic capacitors (or at least several 100 uF's of capacitance) are needed following a 3kw boost PFC stage?
How have they avoided having a proper post PFC capacitor bank?
We wondered if perhaps it was not PFC'd? ..but then surely PFC is essential for 3300W single phase mains chargers, or else the reactive current is going to be too high and they wouldn't be able to draw enough current to get 3300W output from the single phase mains...since it is illegal to draw more than 16A from a single phase mains socket.
What topology do you think they have used?...and how have they avoided a significant post PFC cap bank?
(We cannot remove the bottom PCB as it is glued down, and has the FETs layed flat underneath it. Theres no room there though for electrolytic caps)
We are using a 3.3kw Brusa NLG514 electric car battery charger (Air-cooled, mains powered). We dropped it many times and thought something was loose inside, so opened it up.
We saw absolutely no electrolytic capacitors at all!
Brusa NLG514 charger.
**broken link removed**
There were two separate film capacitor banks of about 6uF each, that was it!!
The power transformer was potted into the corner so we could not see it. (~65mmby65mmby45mm)
We saw two torroids in one of the side panels which we assumed must be boost PFC inductors but dont know because they are sandwiched inside two panels.
Surely electrolytic capacitors (or at least several 100 uF's of capacitance) are needed following a 3kw boost PFC stage?
How have they avoided having a proper post PFC capacitor bank?
We wondered if perhaps it was not PFC'd? ..but then surely PFC is essential for 3300W single phase mains chargers, or else the reactive current is going to be too high and they wouldn't be able to draw enough current to get 3300W output from the single phase mains...since it is illegal to draw more than 16A from a single phase mains socket.
What topology do you think they have used?...and how have they avoided a significant post PFC cap bank?
(We cannot remove the bottom PCB as it is glued down, and has the FETs layed flat underneath it. Theres no room there though for electrolytic caps)