Rotary converter?
Its a motor turning a generator.
Motor and generator can be selected for the kind of power that is needed. Say 3 phase 400V 50Hz motor running a 48V DC generator. Or single phase 60Hz AC motor turning a 3 phase 400Hz AC generator. In some cases the same motor can be used as a generator simultaneously.
With the advancement of power electronics they have been mostly replaced with switchmode power supplies/inverters. They are still commonly used tho for making 3 phase power out of single phase power(In the US its difficult to get 3 phase power in residential areas so people with machine shops use them to run 3 phase machines).
But yes your specifications for this 10kW power supply are a bit sparce.
Does it need to be variable from 0 to 600V?
Does it need to be regulated?
What is the input power to it?
Does it need to be isolated from mains?
Does it require any current limiting functionality?
The huge rack mount PSUs that users are suggesting above indeed cover all of these questions above. But as people have said they these kW cost kilodollars. Don't be surprised to find most of them costing over $5000. But if you have the money you just need to call up TDK or Keysight and soon after have a huge heavy box show up at your front door.
If you don't have the kilodollars then its ebay (Will still cost easily 500 bucks tho) or drop some of the above requirements to let you use a more crude PSU solution (Like rectified mains)