I am asked to design a dc-dc converter with the following specifications: Vin=24V(2 lead-acid batteries in series), Vout=300V and Iout=1A.
My initial choice of topology was the boost converter. Problem is the gate drive duty cycle can go up as high as 1 - 24/300 = 92%, and that's assuming perfect efficiency.
A tapped-inductor boost would solve the duty cycle issue, but at the cost of added complexity.
I am also not sure if the boost family is the way to go at the 300W level.
What dc-dc topology would you recommend for my application?
Okay so my main problem is that the duty cycle at the specified load reaches well above 90%. Research tells me that it's not a good idea to push the duty limits of dc-dc IC controllers. Such a very high duty also means high current stresses on the switches. At 92% (ideally), the average switch current goes around 1A / (1-0.92) = 12.5A. That's a lot of current to handle. Same trend goes for the rest of the components.
One idea to fix this is to use a tapped-inductor boost topology such as this one tapped-inductor http://www.edn.com/ContentEETimes/Images/power_tip_62_fig1.jpg! This way, the needed duty cycle goes down thanks to the added voltage boost from the transformer, and so component stresses are relaxed. However, the transformer adds to the complexity.
I have not explored, and am not knowledgeable, with other dc-dc topologies that can step-up the voltage such as the buck-boost, and forward converter topology. Maybe other such topologies can step-up the power more efficiently compared to the boost and tapped-boost based ideas I gave - I am not sure. My only other concern is the complexity of implementation, as this only an undergraduate project :)
Should I push through with the boost-based idea? If not, what topology would you recommend?