Want to convert step-pulley drive to digital speed control

I have a 3HP three phase mill-drill that I would like to upgrade to
some kind of digital variable speed control. I am looking for as
close to a bolt-on solution as possible. I am sure there are a ton of
solutions out there, I am just not sure where to start.
I am using a static phase converter on the motor right now, I am not
sure if that is a limiting factor or not.

Thank you,

Steve