VFDs for AC motor control are common items, and not too expensive. 3 phase AC motors are everywhere, easy to find used, last forever, and are very inexpensive for their HP rating.
The VFD drives I have seen all take AC input, 1 phase or 3 phase. Since the AC gets converted into DC inside the drive, it would *seem* that DC input versions would be easy (hah!) to convert from existing units, or should be cheaper to buy (due to less parts) then the original AC input versions.
Does/has anyone know/tried this or have any other information?
What would be ideal is if the VFD drive would send power back to the DC buss during regeneration instead of dumping it into load resistors, but I doubt that is possible with a standard unit.
Here are examples of VFD drives.
http://web4.automationdirect.com/adc...Vector_Control)
Thoughts? Pointers? Links?