Check out this forum. It's dedicated to rotary phase convertors (RPC) and VFD's. There are some posters who work for some of the manufacturers who provide a lot of guidance. That's where I've gotten much of the info I've used to build my RPC.
This is a subforum on the Practical Machinist forum. Most of their machines are 3-phase and there are many people who need to run them from single phase power. My personal application was woodworking machinery, but the principles of building the RPC are the same.
It will take some time to read through all of the posts. Phase Converters and VFDs