Hi Guys,

I'm new into power electronics and I would like to design a dc/dc step down module for my project.
Input:
U: 48v - 75v
Output:
U: 0V - input.
I: ±20A

Usually I'd create a buck converter and control this with a micro controller. But since the output power is quite high I can't really find a chip in this range.

I looked into power MOSFETs and PWM controllers for this but I couldn't simulate something properly so far.

Do you guys have any tips for me? Any reference scheme I can look into? I've been googling for 3 days now but most of the result where <100w...

Thanks

 

I'd give you the same advice if you were grinding large telescope mirrors. Make a smaller one before you swing for the fences. Seriously. This should not be your first design.

 

Hello @hoefnageltom ,
First of all, as Papabravo says, this is by no means a quick easy project like using a buck converter chip. If you have 75v at 20A that's1.5kW, which is sizable for DC-DC.
What you will have to do is build an inverter to turn your dc into ac, then send it through a transformer, and rectify, smooth, and regulate the output on the other side. You will need a micro-controller to provide a square wave signal to a mosfet driver, which will then be connected to your power mosfet(s). On the secondary winding you then get a more sinusoidal wave rather than square, which allows you to connect up a triac for switching at a given voltage level. You then add some adjustable voltage regulators, and have a microcontroler aim just above the target voltage before the regulators.
Not a simple project, but would certainly be an interesting one!