These guys make single phase VFDs.
https://www.ato.com/5hp-vfd-single-phase-input-output
I would love to try to implement one for a house air conditioner. The issue would be setting up a programmable thermostat to work with it. It has RS-485 capability, so the programmable thermostat would have to be able to send RS-485 or a 4-20mA setpoint. It would need an RTD with a 4-20mA output.