what topology for pfc and DC-DC has be used , which has commercial benefit?

 

what topology for pfc and DC-DC has be used , which has commercial benefit?

What would be the intended input power source? To get 30kW out you'll need approximately 35 kW of input power if your device is 85% efficient.

I think you need to supply more information. Specifically do you want:

1. 30kV @ 1 Ampere
2. 1V @ 30K Amperes

There is a huge difference aside from the potential lethality. Your need to ask the question tells me that you probably lack the knowledge and the skills to pursue this project. If you do want to get there eventually, I would suggest a sequence of more modest steps.

I'm not sure what you mean by "commercial benefit". If you mean an inexpensive design that can be economically produced and sold at a high markup, then I'm afraid you will encounter intense disappointment.