Normally i love to dream about solutions but this one is a no starter.
Home made Inverters at 380v are dangerious, add 3 phases, well you do the maths. Then on top of that feed it into a motor that will run 1500 rpm where the phases could go out of sync.
Sorry this is not a project to learn on and if this is a school project and you come here you need to go back and do the theory again.
Sorry bout that.
Daz