I’m a retired USAF Lt Col 25 years in service and 20 years as Industrial Electrician. I have always tinkered with electronics but this project is above my pay grade. I need some help. I have a single phase 120v 60Hz ¾ HP drill press I wish to convert to a VFD controlled by Arduino. I found this circuit on Single Phase Variable Frequency Drive VFD Circuit | Homemade Circuit Projects.
With my limited understanding of what is happening here, I think everything to the left of the4017 (IC3) can be replaced with the Arduino. I know it is a big ask however I need help with the schematic and programming. Any help will be greatly appreciated.
I wouldn't start on live circuitry like that, its way too dangerous because you'll have to go through a lot of debugging and burnt out components in all likelihood, and you want to be working on safe low voltage stuff initially.
In my experience with high power MOSFET bridges anything that physically can go wrong will go wrong unless there's robust protection circuitry to prevent it.
Work on a low voltage version initially, basically an inverter circuit, and when you are happy it works well then think about adding a fast-opto-coupled IPM as the output stage. IPM - "intelligent power module" is basically a unit with all the high voltage stuff (MOSFETs, drivers) in one module with an (usually isolated) heat-slug.
Keeping all the mains stuff the other side of opto-isolators is by far the best way to do things, all the control stuff is at ground potential and easy to debug.
I would serious recommend making baby steps towards this goal, a low voltage DC motor H-bridge design being a good first step (check out the HIP4081A chip for a good H-bridge driver available in DIP).