DC-DC converter with high power density

[Selvam_Perumal]

Can anyone suggest suitable DC-DC converter topology for converting 300 V to 50V with isolated output power of 2000W at higher efficiency and less size.

 

[CataM]

Phase shifted full bridge, also known as Zero Voltage Transition (ZVT) converter.

 

[KlausST]

Hi

at higher efficiency and less size.

Higher efficiency ... than what? Higher then 50% is easy.
Less size ...than what?

Klaus

 

[Easy peasy]

also full bridge LLC works well for fixed Vin Vout ...

 

[Selvam_Perumal]

Will Phase shifted ZVT have higher efficiency for my input voltage range(300 to 360V) compared to Full bridge LLC.

 

[treez]

Ditto and add sync rects to the output for your efficiency.
Otherwise paralleling converters if its small enough still.
What about 300v to 300v isolated LLC, then a load of parallel bucks, each with small pulse transformer drive to hi side fet and source current sense in high side.
Less current in the txfmr may mean smaller and your small bucks coudl be malleable and give you small size.

 

[FvM]

my input voltage range(300 to 360V)

Does it mean you need voltage variation/regulation capability? Not mentioned before.

 

[treez]

Will Phase shifted ZVT have higher efficiency for my input voltage range(300 to 360V) compared to Full bridge LLC.

ah...yes, the LLC gets worse in effic when you start having variable vin and/or vout.
But still id go for LLC for that 300-360vin..better efficiency.

- - - Updated - - -

In any case, what you would want is a modified Phase shift full bridge as the following...
https://www.edaboard.com/showthread.php?t=342663

..the "standard" phase shift full bridge converter leaves much to be desired...as the above thread points out.

- - - Updated - - -

Also, with your wider range input...the LLC could be made to be controlled to have same ratio vout/vin....so in other words.....say 300v to 300v, or 360v to 360v....and then have the parallel bucks to do the final high current bit down to 50v. Bucks tend to be small.

 

[CataM]

In any case, what you would want is a modified Phase shift full bridge as the following...
https://www.edaboard.com/showthread.php?t=342663

..the "standard" phase shift full bridge converter leaves much to be desired...as the above thread points out.

"Modified" PSFB are you referring to the addition of 2 diodes in the primary ?

 

[treez]

yes thats some of the mods...but the thread shown in the #8 listed thread shows the other things needed. Its more than just the two diodes...its caps across the fets D-S aswell...and more