I run a lathe with 3HP motor off a VFD with voltage-doubler input. It's a bit of a bodge put together some years ago by a company now out of business. The nice bit is an ABB inverter originally designed for 415V/3P in and out. The third party replaced the input 3-phase bridge with a voltage doubler running off 240V/1P in. It works fine, except towards the upper end of its load capacity. My lathe has a mechanical variable-speed arrangement so I leave the VFD on 50Hz but as the VFD load increases with increasing lathe speed, somewhere north of 2K RPM the DC bus ripple voltage trips the fault-detection circuitry and the thing shuts down with an "input phase error" message (or similar - haven't seen it for a while as I tend to keep the speed down). I'm assuming that the bus capacitors are being, in effect, charged at 25Hz and the voltage sag between input pulses becomes too great.

I have looked longingly at these Ecogoo devices, and I wonder if they actually use a switching voltage boost on the input rather than a simple passive doubler. Also wondered about just putting a chunky transformer plus bridge rectifier in front of my existing VFD but haven't stumbled across anything cheap enough to play with yet.