I would really appreciate some help on this one. I am doing my bachelor's thesis/project which requires me to design and construct a DC-DC converter. I have been working on it for a couple of weeks now.
My main issue is justifying the selection of a specific converter topology. Simply put, I have read a lot about different topologies, been through a lot of literature, but I don't really feel much better off than when I started.
How do I select the appropriate topology for my project? What are the relevant pros and cons?
The requirements are as follows:
- Up to 21 V at max 3 A in voltage mode
- Up to 5 A into minimum 3 ohms, max 21 V in current mode
- Input voltage in the range 26-105 V
- 210 mV output ripple
- Can't use electrolytic capacitors
There are also some requirements for the control loop.
Here is my thought process:
I would prefer to avoid resonant converters as I don't want to open that can of worms. Furthermore, galvanic isolation would be good, but isn't necessarily a strict requirement.
For the flyback and forward topologies, I am a bit concerned about the ripple current in the input capacitor.
I am looking into the following topologies at the moment:
I am open to considering other topologies.
Please ask if anything is unclear or you need any additional clarification.