Topology for Stepping up Voltage

[sabu31]

Hi all,

What topology is commonly used for 48V to 325V boosting at around 1200W. Is two switch forward converter applicable for this power level. And what would the expected efficiency for low complexity topology.

 

[cupoftea]

Is it isolated?
If so, then i would use an LLC....because it can be done with 400V output diodes.
Alternatively, Full Bridge.
Only do 2 Tran Forward if you supply it with a reset voltage via a mini SMPS so that you can have duty cycle up to 75%.
So you need to reset the pri with say 192V....(192v allows you up to 80% duty)

So have a wee regulated bias supply, reg'd to 192V to reset the pri.

 

[BradtheRad]

What topology is commonly used for 48V to 325V boosting at around 1200W

Since you're aware of 2-transistor forward type, you probably know you could choose dual interleaved boost converters. Each On for 84% duty cycle. Non-isolated.

Whichever type you choose, current draw from 48v supply is 30 Amperes average.

 

[sabu31]

Since you're aware of 2-transistor forward type, you probably know you could choose dual interleaved boost converters. Each On for 84% duty cycle. Non-isolated.

Whichever type you choose, current draw from 48v supply is 30 Amperes average.

For interleaved boost converters, in an open loop, the current sharing between converters is unbalanced for any change in duty ratio from 0.5.. How, will efficiencies compare between two-switch forward and dual interleaved boost converter.

Could you share any reference material for the dual interleaved boost converter.

 

[BradtheRad]

Could you share any reference material for the dual interleaved boost converter.

The boost type is less efficient than a few other topologies (containing a transformer). For that reason I hesitated to mention it, but I see from a search the boost design turning up in numerous places as high as 1.2 kW. Youtube has a few videos.

As built singly the boost converter is a simple method (requiring one inductor with one winding). My simulation showing how control pulses can be interleaved. 48v source, 325vDC out, 1.2 kW.

 

[Easy peasy]

Non isolated, 2 phase interleaved booster is a good approach, efficiency can be high for an experienced designer, 12.5 amps per stage + ripple max on the input

Isolated, a full bridge of low Ron mosfets thru a step up transformer with a full bridge of rectifying diodes is a very common and successful approach.

good luck !