It seems very strange that a power supply at only 1500W has a 3 phase input.
I would not want to run it from a variable speed drive. They are designed for highly inductive loads and they often have a lot of fast voltage changes which could cause problems with the power supply.
As the first thing in the power supply is a rectifier, have you tried running it on single phase at 240 V? It might be OK. Problems could arise if the smoothing capacitor isn't large enough or the "open phase" detector (see the data sheet) stops it running.
You could even run it from DC. The input stage of a variable speed drive is a rectifier and smoothing capacitor so you could just use that much of the drive and connect the DC link to the input of the power supply.
It doesn't seem particularly useful to have a DC link voltage in the variable speed drive and a DC level in the power supply, and to join them by converting to 60 Hz and immediately converting back to DC.