Hello everyone,
I have to design a DC-DC converter of an output power 15kW and it should work on 1-phase 230V to 500V as well as 3-phase 230V to 500V rectified ac.
An output power level at 1-phase 230V to 320V will be 6kW, 320V to 500V will be 9kW. Similarly, an output power level at 3-phase 230V to 320V will be 9kW & 320V to 500V will be 15kW. Which converter topology do you suggest? (output voltage of converter has to be constant throughout the supply range)

 

I have to design a DC-DC converter of an output power 15kW and it should work on 1-phase 230V to 500V as well as 3-phase 230V to 500V rectified ac.

Why do you "have to "design this?
If you need to ask on forums how to do this then plainly you should not try to design this!
This is not a trivial project, not to mention the extremely dangerous side of it.
Best stick to a commercial unit or design house.

 

I have to design a DC-DC converter

But you appear to be describing an AC to DC converter...

An output power level at 1-phase 230V to 320V will be 6kW, 320V to 500V will be 9kW. Similarly, an output power level at 3-phase 230V to 320V will be 9kW & 320V to 500V will be 15kW.

output voltage of converter has to be constant throughout the supply range

(Re: your OP) You seem to be under some misapprehension -- 'Phase' is not a property of 'continuous' (i.e. non-time variant) direct current... Getting past that - Perhaps you are stipulating a DC power output requirement of 6kW - 9kW while operating from single phase (AC) input and 9kW-15kW when operated from 3θ (AC) input?

1-phase 230V to 500V as well as 3-phase 230V to 500V rectified ac.

---Emphasis Added---

Inasmuch as the AC input EMF ranges are identical, I fail to see the significance of the AC supply arrangement (i.e. 1θ vs 3θ)? -- Please elucidate

Best regards
HP