Regenerative control gives a motor the capability to act as a generator while in operation. Energy is regenerated during the braking process (regenerative braking) and the output of energy is supplied to an electrical load. Regenerative DC drives are often called “regen drives” for short.
In its basic form, a regenerative braking system recovers energy by slowing the motor, and then it actually recycles the energy. For phase-controlled DC drives, regenerative control involves reverting mechanical energy from an armature and the rotating load back onto the AC power line. The motor’s reversal of current causes the rotation of the load to slow down with braking action.
What’s Required for Regeneration?
For regeneration to occur, the regen drive must be running as well as be energized. If the normal stop command is used to slow the motor, then regenerative stopping occurs. This is called a ramp stop, meaning the motor drive will regenerate and decelerate as needed to follow the decel ramp. Some have a mode for current limit stop as well, so the decel ramp is bypassed and current limit deceleration occurs.
In regenerative control, the regenerated energy from rotation is not dissipated, but it is converted for use elsewhere. The drive and motor can both handle a certain amount of regeneration without doing damage to either.
In general, a drive with regenerative control functions features twice the circuitry and power components as a nonregenerative motor drive. It is also more expensive; however, the energy, material and time savings make it well worth the investment in many industrial facilities.
Carotron’s Elite Series of DC drives provide a great example of regenerative control products. There are models available for regenerative and nonregenerative needs, covering a motor horsepower range of 5 to 300.
In a world that’s always trying to find ways to “Go Green” regenerative control can provide a great solution for plants and other facilities that want to keep their DC motors in operation and conserve energy in the process.