mlw19mlw91 (Customer) asked a question.
VFD: Regenerative Drive Units: I need to capture energy and put it back into the supply line when I am using an otherwise variable frequency drive to power a load.
I need something that can power and regenerate power from a 3 phase motor to 1PH 220 or 110. I ofcourse know about VFD's, and I know there are regenerative drive units, however, most of the regenerative drive units I've found were intended for DC motors. I'm confused! Are there any common units that would suit my application?
The short answer is NO!.
Industrial Drives are meant to POWER a Motor from an AC Supply.. and Control it as best as it can.. if the Motor ends up 'Making' Electricity in the process the Drive has no way to be able to 'Sync' it back to the AC Line.. that would be like a 'Grid Tie' Inverter for PV Solar Cells.. So the dive ends up blowing the excess electricity off as heat.. that is the most direct way for the VFD to do it..
It really does not matter AC or DC Motor.. the Drive is not designed to do this..
Now a Tesla Car Drive Motor Inverter is designed to do this directly.. and charge back the Batteries of the Car..
The Demand is just not there for this need..
Why do You want to put the power back into the Line?..
Cap
There are VFDs that can put power back on the line. What you are looking for is an active front end but these always put 3 phase back on the line.
most VFDs converter stage is just a bridge rectifier to get to DC then the inverter stage chops up the DC with insulated gate bipolar transistors (IGBT) to approximate an AC signal. A drive with an active front end has IGBTs on both the converter and inverter stages as well as filtering to make sure the power put back on the line is clean.
What we do on most of our production lines is have one large active front end drive and tie all the DC buses for the inverters together (there are fuses and contactors at each drive as well for safety). It is more efficient for another AC drive to use the DC from another drive breaking than it is for the active front end to put it back on the line and the only time the power goes back on the line is when the entire line is slowing down.
EDIT
here is a link
https://www.emainc.net/2015/10/19/vfd-active-front-end/
https://literature.rockwellautomation.com/idc/groups/literature/documents/wp/pflex-wp001_-en-p.pdf
"Are there any common units that would suit my application?"
While I don't know for absolute certain, my guess is NO, as your application is not at all common. For a small motor just dumping the power into a resistor is going to be much more common, sure that is "inefficient" but for a small motor the cost/benefit ratio is poor for the large increase in complexity.
For a much lager motor you might have better luck, I'd think particularity in the case of servos (as compared to VFDs), but still not super common for general purpose, though I'd imagine maybe fairly common on elevators, but that is a specialty application.
Solar applications that feed the grid are common, so the technology certainly exists, but 1kW seems very small and I doubt units that small are very common.