Easiest way is to go buy some RST-5000 power supplies from Meanwell, 2 x the 48V 100A variant - and run them in parallel, 3ph + N + E required for input.
Can be controlled via pins on the connectors - or just let them run - volt adj pot on the back. You can get these for < US $ 1000.00 ea.
230/400 Vac 3 phase wiring requires 17A per phase from your building supply.
Other way is to get some large mains transformers designed 5kVA each and design a 3 phase SCR control ( or buy one of the shelf) put some SCR's ( and diodes for half controlled) on a good size heatsink with fans, get out the spanners, wire up and go - a bit heavier and likely more expensive - but rugged and very long lasting and > 95% re-recyclable ...
Some quite large caps required on the o/p for low ripple - unless you employ 2 x 100A o/p chokes to aid in the filtering ...